Jika f(x)= x-1 , g(x)= x^2+2x+1 nilai a yang mungkin jika (gof)(a)=19 adalah...

f(x) = x - 1
g(x) = x² + 2x + 1
(gof) (x) = (x - 1)² + 2(x - 1) + 1
(gof) (x) = x² - 2x + 1 + 2x - 2 + 1
(gof) (x) = x²

jika (gof) (a) = 19
(gof) (x) = x²
(gof) (a) = a²
19 = a²
a = ±√19