方程组x²-2xy-y²+2x+y+2=0 2x²-4xy-2y²+3x+3y+

先化简在求值(x+y)²-(x-y)(x+y)-(xy)²÷(xy),其中x,y是方程组『3x+2y 求方程组的解,方程组xy/(2x+y)-xy/(2x-y)=3,xy/(2x-y)+xy/(2x+y)=4 解方程组x²-2xy+y²=1 2x²-5xy-3y²=0 解方程组x+y=xy,x+2y=xy² 3x²y+xy²-[2xy²-4x²y+（x²y-2xy²） (2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&# 2x²-3xy=y²=0（x,y不得o）求x/y+y/x 解方程组:x²+2xy+y²=1 2x²-xy=0 已知2X-3√xy-2y=0(x>0)求2x²+xy-9y²分之x²+4xy-16y
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy) 解方程组x²-xy-2y²=0 x+y=2