（xy+1)(x+1)(y+1)+xy
热心网友
（xy+1)(x+1)(y+1)+xy=（xy+1)〔xy+(x+y)+1〕+xy =(xy+1)＾2+(xy+1)(x+y)+xy =（xy+1+x)(xy+1+y)注：最后一步为十字相乘得到。
热心网友
（xy+1)(x+1)(y+1)+xy=（xy+1)〔xy+(x+y)+1〕+xy=(xy+1)＾2+(xy+1)(x+y)+xy=（xy+1+x)(xy+1+y)
（xy+1)(x+1)(y+1)+xy
（xy+1)(x+1)(y+1)+xy=（xy+1)〔xy+(x+y)+1〕+xy =(xy+1)＾2+(xy+1)(x+y)+xy =（xy+1+x)(xy+1+y)注：最后一步为十字相乘得到。
（xy+1)(x+1)(y+1)+xy=（xy+1)〔xy+(x+y)+1〕+xy=(xy+1)＾2+(xy+1)(x+y)+xy=（xy+1+x)(xy+1+y)