Question

Let $f(x) = 4x - 7$, $g(x) = (x + 1)^2$, and $s(x) = f(x) + g(x)$. What is $s(3)$?

Answer 1

21

Explanation:

We find that s(x) = 4x - 7 + (x + 1)^2. Expanding, we get s(x) = x^2 + 6x - 6. Plugging in x = 3, we have s(3) = 3^2 + 6 x 3 - 6 = 21.

Alternatively, we can compute that f(3) = 5 and g(3) = 16, so s(3) = f(3) + g(3) = 21.

Answer 2

s(3)=4(3)-7+(3+1)^2

s(3)=12-7+16

s(3)=21