\[(8x + 10)(3 - x) =\]
\[= (11 - 2x)(4x + 5) - 5\]
\[24x - 8x^{2} + 30 - 10x =\]
\[= 44x + 55 - 8x^{2} - 10x - 5\]
\[- 20x = 20\]
\[x = - 1\]
\[Ответ:\ - 1.\]