数学化简题有点难不过做

1）（a+b)(a+b）-（a-b)(a-b)
=a^2+2ab+b^2-a^2+2ab-b^2
=4ab

2) (3x-2y)(3x-2y)-(3x+2y)(3x+2y)
=9x^2-12xy+4y^2-9x^2-12xy-4y^2
=-24xy

3) (a+b)(a-b)-(b+a)(b-a)
=a^2-b^2-b^2+a^2
=2a^2-2b^2

4) (3a+2b)(3a-2b)+(3a-2b)(3a-2b)
=9a^2-4b^2+9a^2+4b^2-12ab
=18a^2-12ab
=6a(3a-2b)

5）（a+b+c)(a+b+c)-(a-b-c)(a-b-c)
=a^2+b^2+c^2+2ab+2ac+2bc-a^-b^-c^2+2ab+2ac-2bc
=4ab+4ac
=4a(b+c)

6) (2a+b-3c)(2a+b-3c)-(2a-b+3c)(2a-b+3c)
=4a^2+b^2+9c^2+4ab-6bc-4a^2-b^2-9c^2+4ab-12ac+6bc
=8ab-12ac
=4a(2b-3c)

7) (a+2b+3c)(a+2b-3c)-(a-2b+3c)(a+2b-3c)
=a^2+4b^2-9c^2+4ab-3ac-6bc-a^2+4b^2+9c^2-12bc
=8b^2+4ab-3ac-18bc

8) (3x-2y+5z)(5z+2y-3x)+(3x+2y+5z)(3x+2y-5z)
=-9x^2-4y^2+25z^2+12xy+9x^2+4y^2-25z^2+6xy+5yz
=18xy+5yz
=y(18x+5z)

给你几个公式
(a+b)(a+b)=a^2+2ab+b^2
(a-b)(a-b)=a^2-2ab+b^2
(a+b)(a-b)=a^2-b^2
(a+b+c)(a+b+c)=a^2+b^2+c^2