Given f(x) = x^2 + 4x, evaluate f(x + 2)

Question

answers

x^2 + 4x + 12

x^2 + 4x + 1

x^2 + 16x + 12

x^2 + 8x + 12

Answer 1

(x+2)^2 + 4(x+2) =

(x+2)(x+2) + 4x + 8 =

x^2 + 4x + 4 + 4x + 8 =

x^2 + 8x + 12

Answer 2

You have f(x) = x^2 + 4x and you have to evaluate for f(x+2).

You have to plug in (x+2) for every x value:

f(x + 2) = (x + 2)^2 + 4(x + 2)

Recall that (a + b)^2 = (a + b) * (a + b), so now you have:

f(x + 2) = (x + 2) * (x + 2) + 4(x + 2)

Now, distribute and use the foil method:

f(x + 2) = x^2 + 2x + 2x + 4 + 4x + 8

Combine like terms:

f(x + 2) = x^2 + 8x + 12

So your final answer will be f(x + 2) = x^2 + 8x + 12

Hope this helps!