(2). Let B, C be two bases for P₂. If B = {x, 1 + x, 1 - x + x²} and the change-of-basis matrix from B to C is
$P_{C \leftarrow B} = \begin{bmatrix} 1 & 0 & 0 \\ 0 & 2 & 1 \\ -1 & 1 & 1 \end{bmatrix},$
please find C. (10%)