diketahui f(x+2)=2x² + 8x + 13 dan g(3x - 1)= 21x - 2. jika (f + g)(x)=14 tentukan nilai x.

f(x+2)= 2x² + 8x + 13
f(x) = 2(x-2)² + 8(x-2) + 13
f(x) = 2(x² - 4x + 4) + 8x - 16 + 13
f(x) = 2x² - 8x + 8 + 8x - 16 + 13
f(x) = 2x² + 5

g(3x - 1) = 21x - 2
g(x) = 21((x + 1) / 3) - 2
g(x) = 21x/3 + 21/3 - 6/3
g(x) = 7x + 15/3
g(x) = 7x + 5

(f + g)(x)=14
2x² + 5 + 7x + 5 = 14
2x² + 7x - 4 = 0
(2x - 1)(x + 4) = 0
x = 1/2   atau   x = -4