liweiye321
幼苗
共回答了24个问题采纳率:79.2% 举报
x²+3x-y-2xy-3y²+2
=(x²-2xy-3y²)+(3x-y)+2
=(x-3y)(x+y)+(3x-y)+2
=(x-3y)(x+y)+[(x-3y)+2(x+y)]+1×2 (十字相乘法)
=(x-3y+2)(x+y+1)
如不明白十字相乘法,可看下面直接提取公因式:
x²+3x-y-2xy-3y²+2
=(x²-2xy-3y²)+(3x-y)+2
=(x-3y)(x+y)+(3x-y)+2
=(x-3y)(x+y)+(x-3y)+2(x+y)+2
=(x-3y)(x+y+1)+2(x+y+1)
=(x-3y+2)(x+y+1)
1年前
5