{2×5+x(y-5)=19 2×5+x(1.5y-5)=31怎么解?
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
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
X+Y=5.7 1/4X+2/5Y=4/5X 怎么解
x-y / 5y= (y-x)^2 / ( )
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
(3x-5y-11)*(3x-5y-11)+|9x+2y-16|=0怎么解?
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
解方程{2x+y=2、-x+y-5
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
这题怎么解?X-Y=4,2X+Y=20,X=?Y=?3X+2Y=14,2X-3Y=5,X=?Y=?