jika diketahui f(x) = x2 + 2x + 1 dan g(x) = x - 1, serta (fog) (x) = 4, maka nilai x yang memenuhi adalah....

f(x) = x² + 2x + 1
g(x) = x - 1

(f o g) (x) = 4
f(x - 1) = 4
(x - 1)² + 2(x - 1) + 2 = 4
x² - 2x + 1 + 2x - 2 + 2 = 4
x² + 1 = 4
x² = 4 - 1
x = ± √3
x = 3 atau x = -3