1. Jika f(x)=x²+1 maka f(f(x))= 2. Diketahui f(x)=²log (x+⅓ dan g(x)= ²log(x+7) maka f(5)+g(5)=

jawab

1. f(x) = x² +1
f{ f(x)} = f (x² +1) = (x² +1)² + 1
f(f(x)) = x⁴ + 2x² + 1 + 1
f(f(x)) = x⁴ + 2x² + 2

2. f(x)= ² log (x +1)/3  dan g(x) =  ²log(x+7)
f(5) = ²log(5+1)/3 = ²log (6/3) = ²log 2 = 1
g(5) = ²log (5+7) =²log 12 = ²log 2² + ²log 3
g(5) = 2 + ²log 3

f(5) + g(5) = 1 + 2 + ²log 3 = 3 + ²log 3