Question

If f(x) = $x^2$ + 1 and g(x) = x - 1, then fog(3) =.

• A. 6
• B. 5
• C. 7

Answer 1

The correct option is B 5

f(x) = $x^2$ + 1, g(x) = x - 1
fog(x) = f{g(x)}
fog(x) = f{x - 1}
fog(x) = ${(x-1)}^2+1$
fog(x) = $x^2$ - 2x + 1 + 1
fog(x) = $x^2$ - 2x + 2
So, fog(3) = $3^2$ - 2(3) + 2
fog(3) = 9 - 6 + 2
fog(3) = 5