因式分解题，拆添项，换元，要过程

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）

1.=（x^2-2x)-(x-2)
=(x-1)(x-2)

2.=(x^3-7x^2)+(7x^2-49x)+(x-7)
=(x-7)(x^2+7x+1)

3.=(x^3-4x^2)-(x^2-4x)+(x-4)
=(x-4)(x^2-x+1)

4.=(x^2+3x)(x^2+3x+2)+1
=(x^2+3x+1)-1)(x^2+3x+1+1)+1
=(x^2+3x+1)^2

5.应该是这个，不然不能分解
（xy-1)²+(x+y-2)(x+y-2xy)
（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

1.=（x^2-2x)-(x-2)