Dik: f(x+2) = 2x²+8x+13 dan q(3x-1)= 21x-2 jika (f+q)(x)=14 tentukan nilai x tolong pakai cara

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) = 7(x + 1) - 2
g(x) = 7x + 7 - 2
g(x) = 7x + 5

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

HP : {-4 , 1/2}

jawab

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) = 7(x+1) - 2
g(x) = 7x + 7 - 2
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