已知x²-3xy+4x=3,y²+xy-4y+7=0,则xy-1/2(x²+y²
已知x²-3xy+4x=3,y²+xy-4y+7=0,则xy-1/2(x²+y²
已知2X-3√xy-2y=0(x>0)求2x²+xy-9y²分之x²+4xy-16y
已知X²+Y²+X²Y²-4XY+1=0 求:(X-Y)^2008-(XY)^2
已知(x+1)²+|y-1|=0,求2(xy-5xy²)-(3xy²-xy)得值
已知x-y=4xy,则2x+3xy-2yx-2xy-y
已知x:y=3:2,求(x²+3xy)/(xy+2xy)
已知(x+y-7)²+|2x-3y-4|=0 求xy得值
已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²)
已知X/Y=2,则X²+2XY-3Y²/X²-XY+Y²=?
已知有理数x,y满足xy=4,x+y=7,则x²y+xy²=()?
已知x²-y²=-8,xy=-3,求5x²-3xy+4y²+11xy-7x
已知X²+Y²=7,XY=-2,求代数式5X²-3XY-4Y²-11XY-7X&