1/2x²+xy+1/2y²=1/2( )=1/2×( )=( )
已知|x+2|+(y+3)²=0,求6xy²-[3x²y-(2x²y-xy
已知1/x-1/y=4,求(2x+xy-2y)/(x-2xy-y)的值
已知 (x+1)² +|y-1|=0,求 2(xy-xy²)-(3xy²-xy) 的值.
分解因式:(X+Y)*(X+Y+2XY)+(XY+1)*(XY-1)
xy(xy+1)+(xy+3)-2(x+y+2分之一)-(x+y-1)的平方
已知x²-xy=4,y²-xy=9求下面代数式的值(1)x²-2xy+y²;(2
已知A=x³-2y³+3x²y+xy²-3xy+4,B=y³-x
已知x=3 y=1\3,求3x²y-[2xy²-2﹙xy-3\2x²y﹚+xy]+3xy&
(1)-2分之1xy(3y²-2xy+3x²y)
(1/2x²y-2xy+y²)×3xy
已知x+y=3,xy=0.5,求(1)2x²y+2xy²的值;(2)x²+y²的
化简!1、(x^2-xy)+xy+y^2 2、3(x^2-xy)-xy+y^2