Vector Spaces & Bases · Hard problem

The vector $\mathbf w = (-6, 4, 8)$ lies in the span of $\mathbf u = (0, -2, -1)$ and $\mathbf v = (-2, 2, 3)$. Find the scalars $a, b$ with $\mathbf w = a\mathbf u + b\mathbf v$.