I have a problem that says: "By using the Gram Schmidt process(if you need it), find an orthonormal basis B in the subspace: $A=\{ u \in R^3 \ | \ x_1-4x_2-x_3=0 \}$
I chose as the basis, $B=\{[1 \ -4 \ -1]\}$ and normed it by dividing each entry with $\sqrt{16}$. Is it correct? How could I use Gram Schmidt? I know how to use it when I have 2+ basis vectors.