先化简再求值(x²+xy-2y²)/(x²-2xy+y²)

先化简再求值(x²+xy-2y²)/(x²-2xy+y²) 数学：先化简再求值(x²+xy-2y²/x²-2xy+y²)-(1-xy 先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y 化简求值：x-y/x²-2xy+y²-xy+y²/x²-y²,其中(x 先化简再求值：2x²+（-x²+3xy+2y²）-（-x²-xy+2y² 先化简再求值-1/2x²×(2xy²-4x²y²)-4x²y×（-xy 先化简再求值,3xy²(xy+2y²-x²)+3x³y²,其中x=2, 先化简,后求值[(x-y)²-(x+y)]/(2xy) 先化简,后求值[(x-y)²-(x+y)]/ 化简求值3x²y-[2xy-2（xy-3/2x²y)+xy]+3xy²其中x=3、y=-1 化简求值3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy² ,当x 化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1, 化简求值(xy-x²)/xy分之x²-2xy+y²乘x²分之x-y,其中y=二分