Gram-Schmidt orthonormalization with polynomials

Question

I'm doing Gram-Schmidt orthonormalization on a sequence of polynomials on $\mathbb{R}[x]$ with $\tau(f,g) = \int_0^\infty f(x)g(x)e^{-x} dx$ and I've got down to a sequence of orthogonal polynomials using the Gram-Schmidt orthonormalization process which are $$\begin{align*}f_0 &= 1\\ f_1 &= x - 1\\ f_2 &= x^2 - 4x + 2\end{align*}$$ (we only have to do three) but how do you make each of these orthonormal rather than just orthogonal?