1,{3x+2y=13 {5x-2y=11 ,2,{5x+2y=25 {3x+4y=15二元一次方程组1,{3x+2y=13 {5x-2y=11 {5x+2y=25 {3x+4y=15

(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) (x+2y)(x-2y)-(2x-y)的平方+(3x-y)(2x-5y)其中x=-1 y=13分之1 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 初二上学期方程题 4x+y=5 5x+4y=63x-2y=1 2x+3y=13x-2y=7 7x+5y=32x+3y=17 2x-y=-4x+5y=6 2x+y=23x-6y=4 3x+2y=52x+y=73x-4y=53x+y=1x-2y=-1x+y=42x+3y=92x-3y=74x+5y=3x+y=20004x+6y=90003x+5y=113x-2y=42x+3y=215x-2y=5x+y=54x+3y=182x+3y=16x+4y=132x+3y=40x 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x （2x+y-1)(2x-y+1)-(3x+y)(3x-y),其中x=5分之1, (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 {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 变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y (x-y)^2+(x+y)(x-y) 其中 X =3 Y=-1 解方程组: ｛3x+2y=13 3x-2y=5 ｛x-y/3=x+y/2+1 2x-5y=9 一、 (x-y)^5÷(y-x)^2-(x-y) 二、 先化简,后求值 (2x-y)^13-[(2x-y)^3]-[(y-2x)^2]^4 其中x=2 y=-1 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=?