9b^2-(a-3b)^2 упростить​

Question

9b^2-(a-3b)^2 упростить​

Answer 1

9b²-(a-3b)²=(3b)²-(a-3b)²=(3b+a-3b)*(3b-(a-3b))=

=(3b+a-3b)*(3b-a+3b)=a*(6b-a).