Question

Factorize 9(a+1)^2-81​

Answer 1

Answer:

The answer is 9(a-2)(a+4).

Step-by-step explanation:

Use $a^{2} -b^{2} =(a-b)(a+b)$  

$9(a+1)^{2} -81= 9( (a+1)^{2}-9)= 9( (a+1)^{2}-3^{2} )= 9(a+1-3)(a+1+3)\\=9(a-2)(a+4).$