Question

F(x) = -4x2 + 9
Find f(-3)

Answer 1

`f(-3)=-27`

Explanation:

So we have the function:

`f(x)=-4x^2+9`

And we want to find f(-3).

So, let's substitute -3 for x. Thus:

`f(-3)=-4(-3)^2+9`

Square. -3 squared is positive 9:

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

Multiply:

`f(-3)=-36+9`

Add:

`f(-3)=-27`

And we're done!