(2a-3b)*(2b+3a) How much is it,

(2a-3b)*(2b+3a) How much is it,

Let's take (2B + 3a) as a whole, so that
Original formula = 2A * (2B + 3a) - 3B * (2B + 3a)
=2a*2b+2a*3a-3b*2b-3b*3a
=6aa-5ab-6bb