用适当的方程解方程组2(x+y)-(x-y)=8 (x+y)-2(x-y)=15 2x+1=5(y+2) (3x+2)-

用适当的方程解方程组2(x+y)-(x-y)=8 (x+y)-2(x-y)=15 2x+1=5(y+2) (3x+2)- 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 解方程组{(x-2)(y+3)=(x+1)(y-1) {(x+1)(y+1)=(x-1)(y+5) 10/x+y+3/x-y=-5 15/x+y-2/x-y=-1（用换元法解此方程组） 如果方程组3x+y=k x+3y=2的解x,y 解方程组：{x+|3x-y|+3y=15 2x+y=6 方程组x-2y=8,3x-4y=5,x=?,y=? 解方程组｛ 3x-4y(x-y)=3 { 2x-3y=1 用代入法解方程组:y=3(x-y),x=2(x-y) 求x+y/3+x-y/2=6 3(x+y)-2(x-y)=28方程组的解 解方程组:(x+3)(y-2)=(x-3)(y+10),(x+1)(y+3)=(x-2)(y+12)