\[2a - 2x + ax - a^{2} = 2 \cdot (a - x) - a \cdot\]
\[\cdot (a - x) = (a - x)(2 - a)\]
\[При\ a = - 2\frac{1}{7};\ \ b = - 3\frac{1}{7}:\]
\[\left( - 2\frac{1}{7} - \left( - 3\frac{1}{7} \right) \right)\left( 2 - \left( - 2\frac{1}{7} \right) \right) = 1 \cdot 4\frac{1}{7} =\]
\[= 4\frac{1}{7}.\]