\[\boxed{\text{938.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[a = 2x - 5;\ \ b = 8x + 1;\ \]
\[\ c = 4x - 2:\]
\[ab - c^{2} = (2x - 5)(8x + 1) -\]
\[- (4x - 2)^{2} =\]
\[= 16x^{2} + 2x - 40x - 5 -\]
\[- \left( 16x^{2} - 16x + 4 \right) =\]
\[= 16x^{2} - 38x - 5 - 16x^{2} +\]
\[+ 16x - 4 = - 22x - 9.\]