Di ketahui f(x+2)=2xpangat2 + 8x + 13 dan g(3x-1)=21x-2 jika(f+g(x)=14 nilai x adalah

f(x+2)= 2x^2 + 8x + 13 misalkan x + 2 = a maka x = a - 2
f(a) = 2 (a-2)^2+ 8(a-2) + 13
f(a)= 2a^2- 8a + 8 + 8a - 16 + 13 
 f(a)=2a^2+5
f(x) = 2x^2+5

g(3x-1)=21x-2  misalkan 3x - 1 = b  maka x =(b+1)/3
g (b) = 21 (b+1)/3 - 2
g (b) = 7b + 7 - 2 = 7b + 5
g(x) = 7x +5

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