若x>y x²+y²=3 xy=1 x-y=
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
x²+xy/(x-4y)(x+y),其中x=4,y=-1
若x+y=10 xy=-1 则x²+y²=(x+y)²-2xy=
若x²+xy+5y=3,y²+xy+5x=-3,求x+y的值.
若x²+xy+5y=3,y²+xy+5x=-3,求x+y的值
若x²+xy+5y=3,y²+xy+5x=-3,求x+y旳值
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,若x
一.x-y=2,则x²-2xy+y²= 二.x-y=-1,xy=3,则x³y-2x
已知x+y=5,xy=3,x³+y³=(x+y)(x²-xy+y²),则1/x&