CLEP College Algebra Exams — CLEP College Algebra Exam Guide
1. What is the greatest common factor of the three terms in the polynomial 12x^4y^2 + 18x²y^4 + 24x³y?
Answer: D
The greatest common factor of the three terms is 6x²y.
The greatest common factor (GCF) of the three terms in the polynomial 12x^4y^2 + 18x²y^4 + 24x³y is 6x²y. This is determined by identifying the highest common factors of the coefficients and the variables in each term.
A) 2xy
2xy is not the greatest common factor because while it is a common factor of the terms, it does not account for the highest coefficients and powers present in all three terms. The coefficients can be factored further, and the variables can also be raised to higher powers, making 2xy insufficient.
B) 2x²y
2x²y is a common factor of the terms, but it is not the greatest. The coefficients of the terms can be factored down to a larger GCF, and thus, while 2x²y appears in each term, it does not encompass the maximum values of the coefficients or the variables.
C) 3x^4y^4
3x^4y^4 cannot be the GCF because it exceeds the powers of variables present in the other terms. Specifically, the term 18x²y^4 has a lower power of x and the term 24x³y has a lower power of y. Therefore, this option is incorrect.
D) 6x²y
6x²y is indeed the greatest common factor as it includes the highest common coefficient (6) and the lowest powers of each variable (x² and y) present in all three terms. This reflects the maximum shared factors among the polynomial's terms.
E) 6x⁹y^7
6x⁹y^7 is not a viable option as it exceeds the powers of x and y found in any of the terms. The highest powers of x and y in the given polynomial do not reach 9 and 7, respectively, making this choice incorrect.
Conclusion
The correct answer, 6x²y, effectively captures the highest common factors of both the coefficients and the variable powers across the polynomial's terms. All other options fail to match this GCF either by being too small or exceeding the limits of the variables involved. Therefore, 6x²y is the definitive greatest common factor.
2. Which of the following is equal to a1/2b1/3a1/4b-2/3, where a > 0 and b > 0 ?
Answer: A
a^3/4/b^1/3
The expression a1/2b1/3a1/4b-2/3 can be simplified to a^(1/2 + 1/4) / b^(2/3 - 1/3), which leads to a^(3/4) / b^(1/3).
A) a^3/4/b^1/3
This option correctly represents the simplified form of the given expression. By combining the exponents of 'a' and 'b' as per the rules of exponents, we find that a^(1/2 + 1/4) simplifies to a^(3/4) and b^(1/3) remains as is, making this option accurate.
B) a^1/8/b^2/9
This option is incorrect as it misrepresents the exponents of 'a' and 'b'. The exponents do not add up to 1/8 and 2/9, indicating a misunderstanding of exponent rules in the simplification process.
C) -a^3/4b^1/3
This choice is incorrect due to the negative sign in front of the expression. The original expression does not contain any negative exponents or terms that would introduce a negative value, thus making this option invalid.
D) -a^3/4b
Similar to option C, this choice is also incorrect because of the negative sign. Additionally, the exponent of 'b' is misrepresented, as the correct exponent should be 1/3, not 1.
Conclusion
Option A is definitively correct as it accurately reflects the simplification of the original expression using the laws of exponents. The other options fail either due to incorrect exponent calculations or the introduction of unnecessary negative signs, demonstrating a misunderstanding of the algebra involved.
3. Which of the following expressions is equivalent to x/(x ^ 2 + 6x + 9) - (x - 3)/(x ^ 2 + 5x + 6) ?
Answer: A
(2x - 9)/((x + 2)(x + 3))
The expression x/(x ^ 2 + 6x + 9) - (x - 3)/(x ^ 2 + 5x + 6) simplifies to (2x - 9)/((x + 2)(x + 3)), demonstrating that this is the equivalent form.
A) (2x - 9)/((x + 2)(x + 3))
Option A is correct as it accurately represents the simplified version of the original expression. The denominators in both fractions can be factored, and upon performing the subtraction, the resulting numerator is confirmed to be 2x - 9.
B) (2x + 9)/((x + 2)(x + 3))
Option B is incorrect because the numerator does not correspond to the result of the subtraction. Instead of 2x - 9, this option incorrectly uses 2x + 9, which does not align with the simplification process of the expression.
C) (2x - 9)/((x + 2) * (x + 3) ^ 2)
Option C is incorrect as it alters the denominator by introducing an additional power to (x + 3) without justification from the original expression. The correct factorization does not require squaring (x + 3) in the denominator.
D) (2x + 9)/((x + 2) * (x + 3) ^ 2)
Option D is also incorrect for the same reason as Option B, where the numerator is incorrectly stated as 2x + 9, and the denominator has an unnecessary square of (x + 3). This does not reflect the correct simplification of the original fractions.
E) (2x + 9)/((x + 2) ^ 2 * (x + 3) ^ 2)
Option E is incorrect due to both a misrepresentation of the numerator as 2x + 9 and an unnecessary squaring of both factors in the denominator. The correct expression does not necessitate such alterations.
Conclusion
Option A is definitively correct as it accurately represents the simplified form of the original expression. All other options fail either by misrepresenting the numerator or incorrectly altering the structure of the denominator, demonstrating a lack of alignment with the mathematical simplification required.
Answer: B
The value of t when the stone hits the ground is approximately 6.2 seconds.
To find the time when the stone hits the ground, we set the height function h(t) to zero and solve for t. The correct value of t that satisfies this equation is approximately 6.2 seconds.
A) 4.5
This option is incorrect because substituting t = 4.5 seconds into the height function h(t) results in a height above ground, indicating that the stone has not yet reached the ground.
B) 6.2
This is the correct option. Substituting t = 6.2 into the height function h(t) results in h(6.2) = 0, confirming that this is the time at which the stone hits the ground.
C) 8.9
This option is incorrect. When t = 8.9 seconds is substituted into the height function, it yields a negative height, indicating that the stone has already hit the ground before this time.
D) 10.4
This option is also incorrect. Similar to option C, substituting t = 10.4 seconds into the height function results in a negative height, which means the stone has already impacted the ground.
E) 12.9
This option is incorrect as well. Substituting t = 12.9 seconds into the height function yields a height below zero, confirming that the stone has already reached the ground well before this time.
Conclusion
The correct answer is 6.2 seconds because it is the only option that results in a height of zero when substituted into the height function, indicating that the stone has hit the ground. All other options either provide a height above ground or a negative height, indicating they do not represent the moment the stone impacts the ground.
5. If z = a + bi = (3+i)(2-3i), then z is equal to which of the following?
Answer: D
z is equal to (9-7i)
To find the value of z, we first need to multiply the complex numbers (3+i) and (2-3i). The result of this multiplication is z = 9 - 7i.
A) (3-7i)
This option is incorrect because, while the imaginary part is consistent with the original multiplication, the real part does not match. The real part of the calculated z is 9, not 3.
B) (3+5i)
This option is incorrect as both the real and imaginary parts do not align with the calculated result. The real part is 9 and the imaginary part is -7, not 3 and 5 respectively.
C) (6-6i)
This option is incorrect since both parts do not correspond to the result of the multiplication. The real part should be 9, and the imaginary part should be -7, not 6.
D) (9-7i)
This option is correct as it accurately represents the result of the multiplication of the complex numbers (3+i) and (2-3i). The calculations yield a real part of 9 and an imaginary part of -7.
E) (9+5i)
This option is incorrect because it inaccurately represents the imaginary part of the result. The calculated imaginary part is -7, not +5.
Conclusion
The correct answer is (9-7i) because it is the accurate result of the expression given in the problem. All other options fail to match both the real and imaginary components derived from the multiplication of the complex numbers.
6. If 0 < r < s < t which of the following CANNOT be true?
Answer: B
B: rt < rs
The statement "rt < rs" cannot be true given the inequality 0 < r < s < t. Since s is greater than r, multiplying both sides of the inequality by r (which is positive) means that rt must be greater than or equal to rs.
A) r ^ 2 < s ^ 2 < t ^ 2
This statement can be true because squaring the values of r, s, and t maintains the order of the inequalities since all values are positive. Thus, r² will indeed be less than s², which in turn will be less than t².
B) rt < rs
This statement cannot be true. Given that s is greater than r, multiplying both sides of the inequality by r (which is positive) yields rt > rs, contradicting the statement.
C) 1/t < 1/s < 1/r
This statement can be true. Since t is the largest among the three variables, 1/t is the largest reciprocal, followed by 1/s, and finally 1/r, satisfying the inequality.
D) s/r < t/r
This statement can be true as well. Dividing both sides of the inequality by r (a positive number) preserves the inequality, confirming that s/r is less than t/r since s < t.
E) r/t < r/s
This statement can also be true. Since t > s, the fraction r/t will be larger than r/s, as dividing r by a larger denominator (t) yields a smaller result compared to dividing it by a smaller denominator (s).
Conclusion
The statement "rt < rs" is definitively incorrect, as it contradicts the established order of the values r and s. All other options logically follow from the relationships defined in the inequalities, demonstrating their validity. Thus, option B is the only choice that cannot be true.
Answer: E
The y-coordinate of the vertex is 9/4.
To find the y-coordinate of the vertex of a quadratic function given its x-intercepts, we can use the formula for the vertex y-coordinate, which is calculated as \( f\left(\frac{x_1 + x_2}{2}\right) \), where \( x_1 \) and \( x_2 \) are the x-intercepts. Here, the intercepts are 3 and -1, which gives a midpoint of 1, and evaluating the function at this point yields a vertex y-coordinate of 9/4.
A) 5/2
This option is incorrect because 5/2 does not correspond to the calculated vertex y-coordinate. To confirm, substituting the vertex calculation shows that the value is lower than what we derived.
B) 8/3
8/3 is also incorrect as it does not reflect the vertex y-coordinate derived from the function's properties. The calculations for the vertex yield a higher value than this option.
C) 7/3
While 7/3 is a plausible value, it is not the correct y-coordinate of the vertex. Evaluating the function at the midpoint of the x-intercepts indicates a value that exceeds 7/3.
D) 11/4
This option is incorrect because 11/4 exceeds the calculated y-coordinate of the vertex. The vertex calculation reveals that the correct value is less than this option.
E) 9/4
This is the correct answer, derived from calculating the vertex's y-coordinate using the average of the x-intercepts. The function's evaluation at the midpoint shows that the vertex indeed has a y-coordinate of 9/4.
Conclusion
The correct choice is 9/4 because it accurately represents the y-coordinate of the vertex calculated from the midpoint of the x-intercepts. All other options fail to reflect the vertex's position based on the properties of the quadratic function given the specified x-intercepts.
8. If log_b(x) = 5, what is the value of x in terms of b?
Answer: D
x = b^5
To solve for x in terms of b when log_b(x) = 5, we can rewrite the logarithmic equation in its exponential form, which gives us x = b^5.
A) 5/b
This option suggests that x is equal to 5 divided by b, which does not align with the exponential relationship derived from the logarithmic equation. Therefore, this option is incorrect.
B) 5b
This option proposes that x equals 5 times b. However, based on the properties of logarithms, the correct transformation leads to x being expressed as a power of b, not a multiplication by b. Thus, this option is incorrect.
C) 5^b
This choice indicates that x is equal to 5 raised to the power of b. This is not a valid representation of the logarithmic equation provided, as it does not maintain the relationship between x and b established by the logarithm. Consequently, this option is incorrect.
D) b^5
This option correctly represents the value of x in terms of b. By using the properties of logarithms, we know that if log_b(x) = 5, then x must be equal to b raised to the 5th power, confirming this option as correct.
E) b^10
This option suggests that x is equal to b raised to the 10th power. However, this does not correspond to the logarithmic equation given, and therefore it is incorrect.
Conclusion
The correct answer, x = b^5, accurately reflects the transformation of the logarithmic equation log_b(x) = 5 into its exponential form. All other options fail to capture the necessary relationship between x and b as dictated by the logarithm, making them invalid.
Answer: C
h(2) equals 1
To find h(2), we need to determine the inverse function of g(x) = x + 1. The inverse function h will reverse the operation of g, allowing us to solve for h(2) effectively.
A) -2
This option is incorrect because if h(2) were -2, it would imply that g(-2) equals 2. However, g(-2) equals -1, not 2, which does not satisfy the definition of the inverse function.
B) [Blank]
This option is not applicable as it is blank.
C) 1
This option is correct. To find h(2), we set g(x) = 2. Solving the equation x + 1 = 2 gives x = 1, which means h(2) = 1. This satisfies the condition that h is the inverse of g.
D) 2
This option is incorrect because if h(2) were 2, then g(2) would need to equal 2. However, g(2) equals 3, which does not satisfy the relationship required for the inverse function.
E) 3
This option is also incorrect. If h(2) were 3, then g(3) would have to equal 2. However, g(3) equals 4, not 2, which does not meet the criteria for the inverse function.
Conclusion
The correct answer is C) 1, as it accurately reflects the value of the inverse function h at the point where g(x) equals 2. All other options fail to satisfy the necessary conditions for inverse functions, demonstrating the importance of correctly identifying how functions and their inverses interact.
Answer: A
y = - 3x ^ 2 - 5
The final equation of the graph after performing the transformations is y = -3x^2 - 5. This equation reflects the vertical stretch, upward translation, and reflection across the x-axis.
A) y = - 3x ^ 2 - 5
This option accurately represents the final transformation sequence. The original equation y = x^2 is stretched vertically by a factor of 3 to yield y = 3x^2, then translated upward by 5 units to become y = 3x^2 + 5. Finally, reflecting across the x-axis results in the equation y = -3x^2 - 5.
B) y = - 3x ^ 2 + 5
This option is incorrect because, while it reflects the vertical stretch by a factor of 3, it does not account for the reflection across the x-axis. The upward translation of 5 units should be negative after reflection, which is not represented here.
C) y = - 3 * (x - 5) ^ 2
This option is incorrect as it alters the x-term in a way that indicates a horizontal shift rather than a vertical transformation. The reflection and translation processes have not been applied correctly, leading to a fundamentally different graph.
D) y = - 3 * (x + 5) ^ 2
This option is also incorrect. Similar to Option C, it modifies the x-term incorrectly, implying a horizontal shift. This does not reflect the transformations described in the problem statement, as it does not follow the correct vertical stretch and reflection.
E) y = 3x ^ 2 – 5
This option is incorrect because it fails to reflect the graph across the x-axis. While it correctly shows the vertical stretch, the upward translation should be negative after the reflection, which is not represented here.
Conclusion
The correct answer, y = -3x^2 - 5, reflects the required transformations accurately: the vertical stretch by a factor of 3, upward translation of 5 units, and reflection across the x-axis. All other options either misrepresent the transformations or incorrectly modify the x-term, failing to achieve the desired final result.