计算18(4x²-xy)-19(4x²-xy)+(4x²-xy-1),
计算18(4x²-xy)-19(4x²-xy)+(4x²-xy-1),
计算:(xy-x²)×x-y/xy
-3(2x²-xy)+4(x²+xy-6)
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
计算x²y³-2x(4xy³)
计算 -3(2x²-xy)+4(x²+xy-6)
-3(xy-2x²)-[y²-(5xy-4x²)+2xy]
因式分解:4x²y+4xy²+xy²
计算:(xy-x²)乘 x-y分之xy
化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1,
计算(-4xy)乘(xy+3x²y)
2x²y+{2xy-[x²y-2(﹣3x²y+xy)]﹣4xy²} 计算