3(3X²Y-2XY²)-4(-XY²+2X²Y-X),其中X=-1/4,Y=2
2xy-1/2(4xy-8x²y²)+2(3xy-5x²y²),其中x=3/2,
合并同类项并计算 -3[y-(3x²-3xy)]-[y+2(4x²-4xy)]其中,x=3,y=1/
化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1,
先化简,再求值:3x²—[2x²y—(xy—x²)]+4x²y,其中x=—1,y
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
化简求值3x²y-[2xy-2(xy-3/2x²y)+xy]+3xy²其中x=3、y=-1
(xy-2y)(xy+2y)-(x-y)²-x²y² 其中x=5/2 y=- 3/5 先化
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
(x²+1/2xy+1/2y²)-(x²+2/3xy-2y²),其中x=-1/4
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
(1).设A=2X²-3Xy+y²+X-3y,B=4X²-6xy+2y²+4X-
|x+2|+(y-1/4)²=0,求2(x²y+xy)-3(x²y-xy)-4x²