3X+Y=20,解X和Y 5X+3Y=15,解X和Y二元一次方程

x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x |x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 解方程组x^3+y^3+x^3*y^3=17和x+y+x*y=5 解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1kkkkkkkk 解方程组,(x+y)^2-3(x+y)=0和x-y=1 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 5X+Y=3 X+5Y=2 求x和y.5X+Y=3X+5Y=2求x和y. 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 {x+y}/2+{x-y}/3=5 {x+y}/2-{x+y}/3=-1 解二元一次方程 3Q!| {x+y}/2+{x-y}/3=5 | {x+y}/2-{x+y}/3=-1 1/(x+y)-1/(x-y)=-3/20,2/(x+y)+3/(y-x)=-(1/5)急啊! 解方程组{(x-2)(y+3)=(x+1)(y-1) {(x+1)(y+1)=(x-1)(y+5) 解分式方程：10/(x+y)+3/(x-y)=-5,15/(x+y)-2/(x-y)=-1 解方程组 3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1 3/(X-Y)+10/(X+Y)=-5 2/(X-Y)-15/(X+Y)=1 解分式方程组