-2x - 3 x ( x - 17 ) = 31 - 2 x ( -x + 25 )
= -2x -3 . x - 17 = 31 - 2 . (-x) + 25
= -2x - 3x + 2x = 31 + 25 + 17
= -3x = 73
= x = $\frac{-73}{3}$
17x + 3 x ( -16x + 37 ) = 2x + 52
= 17x + 3 . (-16x) + 37 = 2x +52
= 17x - 48x - 2x = 52 - 37
= -33x = 15
= $\frac{-15}{33}$