若x²+xy=3,-xy+y²=5,则x²+y²=多少 x²+2xy-
已知x:y=3:2,求(x²+3xy)/(xy+2xy)
若多项式3x²-2xy+y²+kxy-x-5不含xy,则k=多少 快
X²+2xy+y²/xy乘x²-2xy+y²/xy+y²=
若x-y=1,xy=5,则x²y-xy²=?
若(x²-3xy+y+x-5)+3x+1的绝对值=0,则x²-3xy+y-2=多少
已知(x+1)²+|y-1|=0,求2(xy-5xy²)-(3xy²-xy)得值
已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²)
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(
计算:(xy-x²)×x-y/xy
3xy²-[xy-2(xy-3/2x²y)+3xy²]+3xy²,其中x=3,y
已知X/Y=2,则X²+2XY-3Y²/X²-XY+Y²=?
若x+y=10 xy=-1 则x²+y²=(x+y)²-2xy=