If $ \begin{vmatrix} x & z & y \\ a & c & b \\ 1 & 1 & 1 \end{vmatrix} = 7 $, then show that $ \begin{vmatrix} c-b & y-z & zb-yc \\ b-a & x-y & ay-xb \\ a-c & z-x & cx-az \end{vmatrix}=49 $