F(x)=x²+x=1 g(x)=2x+1 Tentukan= a. (fog) (x) b. (gof) (x)

jawab
fungsi

f(x) =  x² +x + 1
g(x) = 2x + 1

a. fog(x) = f { g(x)} = f (2x+1) = (2x+1)² + (2x+1) + 1
fog(x)= 4x² + 4x + 1  + 2x+ 1 + 1
fog(x) = 6x² + 6x + 2

b. gof(x)= g (x² + x + 1)  = 2(x² +  x + 1) + 1
gof(x) = 2x² +2x + 3