Question

Factorise (3a - b)^2-9c^2​

Answer 1

${(3a - b)}^{2} - {9c}^{2} \\ = {(3a - b)}^{2} - {3c}^{2} \\ thus \: by \: solving \: using \: \\ (a + b)(a - b) = {a}^{2}- {b}^{2}\\(3a - b + 3c) (3a - b - 3c)$

Thus your answer is ready

Answer 2

1. (3a-b)^2-9c^2
2. ((3a-b)+9c)((3a-b)-9c)