已知变量x=-3,y=1.x=-2,y=1.5.x=-1,y=2.x=1,y=-2.x=2,y=-1.5.x=3,y=-
若变量x,y满足约束条件{x>=-1;y>=x;3x+2y
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知变量x,y满足约束条件x+2y-3=0,y-1
变量x,y满足x-2y=0,x
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
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
设变量xy满足 x+y-3 x-y+1 3x-y+5 z=x+y/x
已知4x=9y求(1)x+y/y (2)y-x/2x
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1