1) 7(а-5)-b(5-a) при a=2, b=3
7(2-5)-3(5-2)=14-35-15+6=-30
2) a(a-b)+b(b-a) при a=6,3,b=2,3
6,3(6,3-2,3)+2,3(2,3-6,3)=36,69-14,49+5,29-14,49=16
3) 2x(x+y)-3y(x+y)+7(x+y) при x=4,y=5
8(4+5)-15(4+5)+7(4+5)=32+40-60-75+28+35=0
4) x(y-x)-y(x-y)-4(y-x) при x=3,y=-5
3(-5-3)+5(3+5)-4(-5-3)=-15-9+15+25+20+12=48
