Question

Given f(x) = -x2 - x, find f(-9)

Answer 1

-72

Explanation:

Assuming it is -x^2 - x and not (-x)^2, then you simply plus in -9 for x:

-(-9)^2-(-9) = -72

Answer 2

Given the problem:
f(x) = -x^2 - x

Given:
f(-9)

When seeing a problem like this, simply remember that all you have to do is plug in the given f(number) into the x in the equation. So:
f(x) = -x^2 - x
Plug in the -9 for x:
f(x) = -(-9)^2 -(-9)
Evaluate the power:
-(81)-(-9)
Distribute the negative:
-81+9
Add:
-72
That’s your answer!