Решите пожалуйста!!!!!!

Решите задачу:

$1)x^2-25y^2=x^2-(5y)^2=(x-5y)(x+5y);$
$2)(a+3b)(a-3b)=a^2-(3b)^2=a^2-9b^2;$
$3)4x^2-64y^2=(2x)^2-(8y)^2=(2x-8y)(2x+8y);$
$4)(b+2a)(2a-b)=(2a+b)(2a-b)=(2a)^2-b^2=4a^2-b^2;$
$5)(a-4)(a+4)=a^2-4^2=a^2-16;$
$6)(1-x^3)(x^3+1)=(1-x^3)(1+x^3)=1^2-(x^3)^2=1-x^6;$
$7)(x^2-1)(1+x^2)=(x^2-1)(x^2+1)=(x^2)^2-1^2=x^4-1;$
$8)3y^2-27=3(y^2-9)=3(y^2-3^2)=3(y-3)(y+3);$
$9)3x^2+12x+12=3(x^2+4x+4)=3(x+2)^2;$
$10)25x^2-16=(5x)^2-4^2=(5x-4)(5x+4);$
$11)(3x^2+y^2)^2=(3x^2)^2+2*3x^2y^2+(y^2)^2=9x^4+6x^2y^2+y^4;$
$12)(6x-2y^3)^2=(6x)^2-2*6x*2y^3+(2y^3)^2=36x^2-24xy^3+4y^6;$
$13)(a^2+4)^2-16a^2=(a^2+4)^2-(4a)^2=(a^2+4-4a)(a^2+4+4a)=$
$=(a^2-4a+4)(a^2+4a+4)=(a-2)^2(a+2)^2=((a-2)(a+2))^2=$
$=(a^2-4)^2;$
$14)x^2+2xy+y^2=(x+y)^2;$
$15)(a^2-1)^2=(a^2)^2-2a^2+1^2=a^4-2a^2+1;$