已知(x+y)²=7,(x-y)²=5,则x²+y²= xy=
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知有理数x,y满足xy=4,x+y=7,则x²y+xy²=()?
已知实数x,y,xy=5,x+y=7,求代数式x²y+xy²的值
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
已知x+y=5,xy=3,x³+y³=(x+y)(x²-xy+y²),则1/x&
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知实数x,y满足5x²+2y²+1=6xy+4x-2y,则x²-xy+2000y
已知:x/y=4/5,求y²/(x²-xy+y²)的值
已知X/Y=2,则X²+2XY-3Y²/X²-XY+Y²=?
已知xy²=-6,求xy(x^3y^7-3x^2y^5-11.5y)的值
已知x-y=根号5,xy=二分之一,求x²-xy+y²