Question

Разложите на множители:
a) 9(a+1)^2-1 =
б) 4-25(-3)^2 =

Answer 1

1)9a^2-18a+9-1=9a^2-18a+8=(a-4/3)(a-2/3)
2)4-25*(-3)^2=-221

Answer 2

а) $9(a+1)^2-1=(3(a+1))^2-1^2=(3(a+1)-1)(3(a+1)+1)=\(3a+3-1)(3a+3+1)=(3a+2)(3a+4)$; 

б) $4-25*(-3)^2=2^2-(5*(-3))^2=(2-5*(-3))(2+5*(-3))=\(2+15)(2-15)=-13*17$.