1,x³-3x+2=(x-1)(x²+x-2)
2,x³-48x+7
=x³-49x+x+7
=x(x-7)(x+7)+x+7
=(x²-7x+1)(x+7)
3,x³-5x²+5x-4
=(x³-4x²)-x²+5x-4
=x²(x-4)-(x-4)(x-1)
=(x-4)(x²-x+1)
4,x(x+1)(x+2)(x+3)+1
=(x²+x)(x²+5x+6)+1
=x^4(四次方)+6x³+11x²+1
=(x+3x+1)^2
5,这题是不是打疏忽了?
原题应为（xy-1)²+(x+y-2)(x+y-2xy) 不然无法分解
（x+y-2xy)(x+y-2)+(xy-1)2
=(y2-2y+1)x2-2(y2-2y+1)x+y2-2y+1
=(y-1)2(x-1)2
（跟在后的2为平方）