Answer:
f(x) = (x + 2)2 = 2x + 4
g(x) = 3(x - 1) = 3x - 3
gf(x) = (2x + 4)(3x - 3)
= 6x² - 6x + 12x - 12
= 6x² + 6x - 12
To write the final answer in the form
a(x² + bx + c) we factorize the expression
Thus
6x² + 6x - 12
= 6( x² + x - 2)
where a = 6, b = 1 and c = - 2
b.) to find g '(12) we first find g ′
To find g′ equate g(x) to y
Thus
g(x) = y
y = 3x - 3
x = 3y - 3
3y = x + 3
Divide both sides by 3
We get
y = x+3/3
That's g′ = x + 3 / 3
g′(12) = 12 + 3 / 3
= 15/3
= 5
Hope this helps
