Разложите на множители 1)25^2-81y^2 2)0.09-0.16c^2 3)9a^4-49b^6 4)(8+6x)^2-1

1) (5-9y)(5+9y)
2)(0.3-0.4c)(0.3+0.4c)
3)(3a^2-7b^3)(3a^2+7b^3)
4)(8+6x-1)(8+6x+1)=(7+6x)(9+6x)

1). 25^2-81y^2=(5-9y)(5+9y)
2).0,09-0,16c^2=(0,3-0,4c)(0,3+0,4c)
3).9a^4-49b^6=(3a^2-7b^3)(3a^2+7b^3)
4).(8+6x)^2-1=(8+6x-1)(8+6x+1)=(6x+7)(6x+9)