3y-2x=1 x+2/3=y+1/4对对答案还有一个 x+y/3+x-y/2=6 3(x+y)-2(x-y)=28

{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 x^3=y^3+2y^2+1 求所有整数数对（x,y) 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 [(y-2x)(-2x-y)+4(x-2y)平方]/3y,其中x=1,y=-3 y=x^5+√x+1/x^3 ,求导数结果是y’=2x-5/2x^-7/2-3x^-4,对y求导数 [(2x+y)^2+(y+2x)(y-2x)-2y(4x-y)]/4y,其中x=1/2,y=1/3 先化简,再求值：[(x+y)(x-y)-(x-y)^2+2y(x-3y)]/(-4y),其中x=1,y=-2 (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 9y=3x-(x-1),4(x+y)-(2x+4)=8y 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y