问几个初中数学分解因式题

a^2-81 =(a-9)(a+9)
36-x^2 =(6-x)(6+x)
1-16b^2 =(1-4b)(1+4b)
m^2-9n^2 =(m-3n)(m+3n)
0.25q^2-121p^2 =(0.5q-11p)(0.5q+11p)
169x^2-4y^2 =(13x-2y)(13x+2y)
9a^2p^2-b^2q^2=(3ap-bq)(3ap+bq)
(m+n)^2-n^2 =m(m+2n)
49(a-b)^2-16(a+b)^2 =(3a-11b)(11a-3b)

(2x+y)^2-(x+2y)^2 =3(x-y)(x+y)
(x^2+y^2)^2-x^2y^2=(x^2+y^2-xy)(x^2+y^2+xy)
3ax^2-3ay^4 =3a(x-y^2)(x+y^2)
p^4-1=(p-1)(p+1)(p^2+1)

1.
a^2-81=(a-9)(a+9)

2.
36-x^2
=-(x^2-36)
=-(x-6)(x+6)

3.
1-16b^2
=-(16b^2-1)
=-(4b-1)(4b+1)

4.
m^2-9n^2=(m-3n)(m+3n)

5.
0.25q^2-121p^2=(0.5q-11p)(0.5q+11p)

6.
169x^2-4y^2=(13x-2y)(13x+2y)

7.
9a^2p^2-b^2q^2=(3ap-bq)(3ap+bq)

8.
(m+n)^2-n^2
=[(m+n)-n][(m+n)+n]
=m(m+2n)

9.
49(a-b)^2-16(a+b)^2
=[7(a-b)-4(a+b)][7(a-b)+4(a+b)]
=[(7a-7b)-(4a+4b)][(7a-7b)+(