Rebuilding a Vector From Two Others

You are given three vectors in $\mathbb{R}^3$:

$\mathbf{u} = (1,\ 2,\ -1), \qquad \mathbf{v} = (3,\ -1,\ 2), \qquad \mathbf{w} = (11,\ 1,\ 4)$

Find scalars $a$ and $b$ with

$\mathbf{w} = a\mathbf{u} + b\mathbf{v}$

or decide that no such scalars exist. All three coordinates must match — a pair that works for two of them is not an answer.