2x+5y=12,2x+3y=6,解是什么急@!快

x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 解方程组：x+y/2+x-y/3=6 4(x+y)-5(x-y)=12 2(x-2y)²-7(x-2y)³+3(2y-x)²+(2y-x)³合并同类项 这个式子2（x-2y)²-7（x-2y)³+3(2y-x)²-(2y-x)³=2（x-2y)²-7（x-2y)³+3(x-2y)²+(x-2y)³=5(x-2y)²-6(x-2y)³=(x-2y)²(5-6x+12y) 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 3x+5y-(x+y)=6 2(x+y)-3x=-7 12y(x-y)^2-8(x-y)^3=? （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1