Question

几道计算和因式分解！急！

1.a(a-b)-b(b-a) 2.4x(a-b)-8y(b-a) 3.3x(x^2-2x-1)-2x^2(x-3) 4.(x^2-5)^2+8(x^2-5)+16
追问：(x^2-1)^2什么意思？

Answer 1

1、原式=(a-b)(a+b)

2、原式=4(a-b)(x+2y)

3、原式=3x(x^2-2x-1)-2x^2(x-3)

            =3x^3-6x^2-3x-2x^3+6x^2

            =x^3-3x

            =x(x^2-3)

4、(x^2-5)^2+8(x^2-5)+16

   =(x^2-5+4)^2

   =(x^2-1)^2 

(x^2-1)^2的意思就是

Answer 2

1.a(a-b)-b(b-a)
=a(a-b)+b(a-b)
=(a-b)(a+b)
2 .4x(a-b)-8y(b-a)
=4x(a-b)+8y(a-b)
=(a-b)(4x+8y)
3.3x(x^2-2x-1)-2x^2(x-3)
=3x^3-6x^2-3x-2x^3+6x^2
=x^3-3x
=x(x^2-3)
4.(x^2-5)^2+8(x^2-5)+16
=(x^2-5+4)^2
=(x^2-1)^2