(1)-49/y^2+16/x^2=
3分之2(X-Y)-4分之X+Y=-1,6(X+Y)-4(2X-Y)=16
解方程组:2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16
已知集合A={(x,y)| (y-3)/ (x-1)=2,x,y∈R},B={(x,y)| 4x+ay=16,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
1、x(x-y)(x+y)-x(x+y)^2
(3x-y)^2+(3x+y)(3x-y),x=1,y=-2
已知4x=9y求(1)x+y/y (2)y-x/2x
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
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
(1)(x^2/x)-y-x-y