Vector Spaces & Bases · Hard problem

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