Question

If f(x)=−4x^2+15 , then find f(−3).

a) -21
b) -33
c) -51
d) -57

Answer 1

To find f(-3) for f(x)=-4x^2+15, substitute -3 for x, resulting in f(-3) = -4(-3)^2 + 15, which simplifies to -21.

Step-by-step explanation:

To find the value of f(-3) for the given function f(x) = -4x2 + 15, we need to substitute x with -3 and perform the necessary arithmetic operations.

Substituting x with -3:

f(-3) = -4(-3)2 + 15

First, square -3 which gives us 9. Then multiply by -4, resulting in -36, and finally add 15.

f(-3) = -4(9) + 15

= -36 + 15
= -21

Therefore, f(-3) for f(x)=-4x^2+15, substitute -3 for x, resulting in f(-3) = -4(-3)^2 + 15, which simplifies to -21. The correct answer is (a) -21.