Question 930518
Replace x^2 in the composition with g(x), based on the definition for g(x).



{{{(x^2)^2+2x^2+1}}}
{{{(g(x))^2+2g(x)+1}}}
Formally explaining the rest is hard to do; but you see g(x) was used as replacement for the variable of f(x).
{{{highlight(f(x)=x^2+2x+1)}}}