Question

Find f(3). f(x) = x2 + 5x - 9 A) 7 B) 10 C) 9 D) 15

Answer 1

Answer:

f(3) = 15. Correct: D)

Explanation:

Numeric Value of a Function

The value of a function f(x) when x = a is calculated by replacing the x for a. We have the function:

$f(x)=x^2+5x-9$

It is required to find f(3), or the numeric value of f when x=3. Replace x for 3

$f(3)=3^2+5(3)-9$

$f(3)=9+15-9$

$f(3)=15$

A) Incorrect. f(3) is not 7

B) Incorrect. f(3) is not 10

C) Incorrect. f(3) is not 9

D) Correct. f(3) =15 as found above.