Question

Given the function f(x) = -2x2 + 4x - 7, find f(-4).
-55
-7
25

Answer 1

-2(-4)2+4(-4)-7
16-16-7
-7. -7 is correct

Answer 2

f(-4)= -55

Explanation:

We want to find f(x), or y, when x is equal to -4.

Therefore, we can substitute -4 in for x in the function.

f(x) = -2x^2 + 4x - 7

Substitute -4 in for x

f(-4) = -2(-4^2) + 4(-4) - 7

Evaluate the exponent

f(-4)=-2(16)+4(-4)-7

Multiply -2 and 16

f(-4)= -32+4(-4)-7

Multiply 4 and -4

f(-4)=-32-16-7

Subtract

f(-4)=-55