Answer:
f(2) = 12
f(x) = 7, x = -3, 1
Step-by-step explanation:
a)
plug in x as 2
f(x) = 2^2 + 2(2) + 4
f(x) = 4 + 4 + 4
f(x) = 12
b)
replace f(x) with 7
7 = x^2 + 2x + 4
x^2 + 2x - 3 (move 7 to other side)
Factor
ac: -3x^2
b: 2x
split b into 3x, -x
(x^2 -x) + (3x - 3)
↓ ↓
x(x-1) + 3(x-1)
Factor: (x-1)(x+3) = 0
Solve using Zero Product Property:
x - 1 = 0, x + 3 = 0
x = 1, x = -3
