Question

If f(x) =
(3+x)
(x-3)
what is f(a + 2)?

Answer 1

We have f(x)=(3+x)(x-3)=3x-9+x²-3x=x²-9

So f(a+2)=(a+2)²-9=a²+4a+4-9=a²+4a-5