5,4(3y-2)-7,2(2y-3)=1,2;
16,2y-10,8-14,4y+21,6=1,2;
1,8y+10,8=1,2;
1,8y=-9,6;
y=-16/3;
y=-5⅓
2а (а + b - с) – 2b (а - b - с) + 2с (а - <span>b + с)=2а^2+2ab-2ac-2ab+2b^2+2bc+2ac-2bc+2c^2=2a^2+2b^2+2c^2</span>
6х-4х+18-1 <= 0
2х+17 <span><= 0
2х </span><span><= 17
х </span><span><= 8,5</span>