Math f(x)
posted by anna on .
given f(x)= x^2+x and g(x)=2x+1 determine f[g(x)]
i don't even know where to start with this question help is much needed

well, you know
f(x) = x^2+x, so
f(g) = g^2+g
But, g = 2x+1, so
f(g) = (2x+1)^2 + (2x+1) = 4x^2 + 6x + 2