2。ab+a+b+1=a(b+1)+(b+1)=(a+1)(b+1) 3。ab-a-b+1=a(b-1)-(b-1)=(a-1)(b-1) 4。ab-a+b-1=a(b-1)+(b-1)=(a+1)(b-1) 5。x^3y-x^2y+xy-y=x^2y(x-1)+y(x-1)=y(x-1)(x^2 +1) 1。
a^3-a^2-a+1 =a^3-a^2-(a-1) =a^2(a-1)-(a-1) =(a-1)(a^2-1) =(a-1)(a+1)(a-1) =(a-1)^2(a-1) 2。ab+a+b+1 =a(b+1)+(b+1) =(b+1)(a+1) 3。
ab-a-b+1 =a(b-1)-(b-1) =(b-1)(a-1) 4。ab-a+b-1 =a(b-1)+(b-1) =(b-1)(a+1) 5。x^3y-x^2y+xy-y =x^2y(x-y)+y(x-1) =(x-y)(x^2y+y) =y(x-y)(x^2+1)。
1.a^3-a^2-a+1 =(a^3+1)-(a^2+a) =(a+1)(a^2-a+1)-a(a+1) =(a+1)(a^2-a+1-a) =(a+1)(a^2-2a+1) =(a+1)(a-1)^2 2.ab+a+b+1 =a(b+1)+b+1 =(a+1)(b+1) 3.ab-a-b+1 =a(b-1)-(b-1) =(a-1)(b-1) 4.ab-a+b-1 =a(b-1)+b-1 =(a+1)(b-1) 5.x^3y-x^2y+xy-y =(x^3y-y)-(x^2y-xy) =y(x^3-1)-xy(x-1) =y(x-1)(x^2+x+1)-xy(x-1) =y(x-1)(x^2+x+1-x) =y(x-1)(x^2+1)
1.a^3-a^2-a+1 =a^3-a^2-(a-1) =a^2(a-1)-(a-1) =(a-1)(a^2-1) =(a-1)(a+1)(a-1) =(a-1)^2(a-1) 2.ab+a+b+1 =a(b+1)+(b+1) =(b+1)(a+1) 3.ab-a-b+1 =a(b-1)-(b-1) =(b-1)(a-1) 4.ab-a+b-1 =a(b-1)+(b-1) =(b-1)(a+1) 5.x^3y-x^2y+xy-y =x^2y(x-y)+y(x-1) =(x-y)(x^2y+y) =y(x-y)(x^2+1)
2、3、4我知道，同上一位回答者一样，1、5我不太清楚。
1.(a-1)^2*(a+1) 2.(a+1)*(b+1) 3.(a-1)*(b-1) 4.(a+1)*(b-1) 5.y*(x^2+1)*(x-1)
1.a^3-a^2-a+1=a^2(a-1)-(a-1)=(a+1)(a-1)^2 2.ab+a+b+1=a(b+1)+(b+1)=(a+1)(b+1) 3.ab-a-b+1=a(b-1)-(b-1)=(a-1)(b-1) 4.ab-a+b-1=a(b-1)+(b-1)=(a+1)(b-1) 5.x^3y-x^2y+xy-y=x^2y(x-1)+y(x-1)=y(x-1)(x^2 +1)
答：x^4+4=x^4+4x^2+4-4x^2=(x^2+2x+2)(x^2-2x+2) =(x+1+i)(x+1-i)(x-1+i)(x-1-i)详情>>
