若x+y=1,则1/2x²+xy+1/2y²=
1-x²+2xy-y²
若x+y=1,则1/2x²+xy+1/2y²=
已知x/y=1/2,则x²-3xy+2y²/2x²-3xy+7y²
1.若x=2,y=1,则(x-y)(x²+xy+y²)=______.
计算:(1).(-2xy²)*(3x²y)²
已知x+y=2,则1/2x²+xy+1/2y²
方程组{x²+y²=10(1)x²-3xy+2y²=0(2)怎么解
已知x²+y²+2xy-2x-2y+1=0,则(x+y)^2010=
若多项式x²-2xy+y²-x+y-1=0,求x-y的值.
已知|x+2|+(y+1²=0,求x²+(2xy-3y²)-2(x²+xy-2y
若xy=1,则(x+y)²-(x-y)²的值是( )
已知x-2y=3,求1/2x²-2xy+2y²