7x-2y=-3 9x+2y=-19

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 4.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+24.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+2y=21 3x+5y=56 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) x-2y=9 x+y+z=7 2x-3y=12 (x+y)(2x-3y)=? 求解(1){2x-y=9 3x+y=7 (2)｛4x-3y=5.6 5x+3y=7.4 (3)｛2x+3y+19=0 x+5y-1=0(4)｛x+y/2+x-y=1 4（x+y)-5(x-y)=2 7y(x-3y)-2(3y-x)=0 .x=?,y=? 、1.2x+9y=81 3x+y=341.2x+9y=81 3x+y=34 2.9x+4y=35 8x+3y=30 3.7x+2y=52 7x+4y=62 4.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+2y=21 3x+5y=56 7.5x+7y=52 5x+2y=22 8.5x+5y=65 7x+7y=203 9.8x+4y=56 x+4y=21 10.5x+7y=41 5x+8y=44 11.7x+5y=54 3x+4y=38 12.x+8y=15 数学题求解解下列方程组x+y/2 +x-y/3=62(x+y)-x=-49x+7y=397x+9x=41 方程题4道1.4(x-y-1)=3(1-y)+3.5 (x/2)+(y/3)=2 2.2(x-y)/3-(x+y)/4=13/6 6(x+y)-4(2x-y)=16 3.3x-y+z=3 2x+y-3z=9 x+y+z=12 4.5x-4y+4z=13 2x+7y-3z=19 3x+2y-z=18 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 方程组求解：x-2分之1y=1 2x+3y=8 3x-2y=9 x+2y=3 2y=7x+3 9x+2y=19