30. The function f is defined by f(x) = 2x² - 3x + 4 for all values of x. What is the value of f(5)?
Answer: B
The value of f(5) is 39.
To find the value of f(5), substitute x with 5 in the function f(x) = 2x² - 3x + 4. Calculating this gives f(5) = 2(5)² - 3(5) + 4 = 39.
A) 31
Option A is incorrect because substituting 5 into the function does not yield this result. Calculating f(5) results in 39, not 31.
B) 39
Option B is correct as it accurately reflects the calculated value of f(5). Substituting 5 into the function yields f(5) = 2(5)² - 3(5) + 4 = 39.
C) 81
Option C is incorrect; substituting 5 into the function does not give this value. The calculation leads to 39, which is significantly less than 81.
D) 89
Option D is also incorrect as it suggests a value not derived from the function for x=5. The correct calculation clearly shows that f(5) equals 39, not 89.
Conclusion
The value of f(5) is definitively 39, as demonstrated by the substitution into the function. All other options do not reflect the correct evaluation of the function at the specified point, confirming that they are incorrect.