已知x/y=1/2,求(x²-2xy+3y²)/(x²+3xy+2y²)的值
已知x/2=y/3(xy≠0),求x²-2xy-3y²/x²-6xy-7y²的值
已知x+y=4.x-y=6.求代数式xy(y²+y)-y²(xy+2x)-3xy的值
已知x/y=3,求x²+2xy-3y²/x²-xy+y²的值
已知y/X=3,求x²-xy+y²/x²+2xy-3y²的值
已知x/y=2,求x²-xy+3y²/x²+xy+6y²的值
已知x/y=1/2,求(x²-2xy+3y²)/(x²+3xy+2y²)的值
已知x/y等于3,求x²+2xy-3y²/x²-xy+y²的值
已知x-3y=0,y≠0,求x²-2xy+y²分之2x+y×(x-y)的值
已知x²-x-2xy+y+y²,求代数式½(x²+y²)-xy的值
已知xy²=-6,求xy(x^3y^7-3x^2y^5-11.5y)的值
已知x-2y=3,x²-2xy+4y²=11,求下列各值; (1)xy (2)x²-2xy
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值