1、(-3x-4y)·( )=9x²-16y² 2、如果x+y=6,xy=7,那么x²+y
1、(-3x-4y)·( )=9x²-16y² 2、如果x+y=6,xy=7,那么x²+y
x/y=2,求分式x²-xy+3y²/x²+xy+6y²
已知x²y²+x²+y²=10xy-16 求x,y
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y.若x
|x+2y+3|+(2x+y)²=0求x²-xy+y²
设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,若|
设A=2x²-3xy+y²-x+2y ,B=4x²-6xy+2y²+3x-y .
已知x/y=3,求x²+2xy-3y²/x²-2xy+y²
已知x/y=3,求x²+2xy-3y²/x²-xy+y²的值
1 3x²+4xy-y²=
已知X²-5XY+6Y²=0,求(X²+3XY)\2Y²的值
已知xy=-2,x-y=3,求(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy