2b2c2+2c2a2+2a2b2-a4-b4-c4
1个回答

因为

a4+b4+c4-2a2b2-2b2c2-2c2a2

=(a2-b2-c2)2-4b2c2

=(a2-b2-c2+2bc)(a2-b2-c2-2bc)

=(a2-(b-c)2)(a2-(b+c)2)

=(a+b-c)(a-b+c)(a+b+c)(a-b-c)

所以

2b2c2+2c2a2+2a2b2-a4-b4-c4

=-(a+b-c)(a-b+c)(a+b+c)(a-b-c)

2b2c2+2c2a2+2a2b2-a4-b4-c4

=(a+b-c)(a-b+c)(a+b+c)(b+c-a)

供参考!JSWYC