y=2x-6y=-1/2x-1
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
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
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
已知4x=9y求(1)x+y/y (2)y-x/2x
y=(x^2+x)/(x+1)
2(x+y) 3x+3y=24 x+y/2x x y/2y= 1
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
x+y)(x-y)+(x-y)^2-(6x^2y-2xy^2)/2y,其中x=-2,y=1/3
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值
1、x(x-y)(x+y)-x(x+y)^2
x+y/2+x-y/3=5/6;x=y/6-x-y/3=1/2