If f(x)=x+3f(x) = x + 3f(x)=x+3 and (f∘g)(x)=x2(f \circ g)(x) = x^2(f∘g)(x)=x2, what is g(x)g(x)g(x)?
g(x)=x2−3g(x) = x^2 - 3g(x)=x2−3
g(x)=x2+3g(x) = x^2 + 3g(x)=x2+3
g(x)=(x+3)2g(x) = (x+3)^2g(x)=(x+3)2
g(x)=x−3g(x) = x - 3g(x)=x−3