1,5(2x+5)+x=3(0,5x-7)+3,5
1.5(2x+5)+x=3(0.5x-7)+3.5 3x+7.5+x=1.5x-21+3.5 4x-1.5x=-21+3.5-7.5 2.5x=-25 x=-25/2.5 x=-10
3x+7,5+x=1,5x-21+3,5; 4x+7,5=1,5x-21+3,5; 4x-1,5x=-7,5-21+3,5; 2,5x=-25; x=25:2,5; x=10. Ответ:x=10.
X = -10