3x²-2xy-y²+2x+6y=8,2x²-3xy-5y²+3x+17y=14
已知x/y=2,求x²-xy+3y²/x²+xy+6y²的值
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
已知xy²=-6,求xy(x^3y^7-3x^2y^5-11.5y)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
(x+3y)(x-y)-(x+y)^2 =x²-xy+3xy-3y²-x²-y²
一.x-y=2,则x²-2xy+y²= 二.x-y=-1,xy=3,则x³y-2x
已知x+y=4.x-y=6.求代数式xy(y²+y)-y²(xy+2x)-3xy的值
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(
1 、x+y=8 xy=6 求x²+3xy+2y²/x²y+2xy²
2x²-3xy=y²=0(x,y不得o)求x/y+y/x
已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²)