(3a-2a+1)²-(a-2b)(a+3b)
=(a+1)²-(a-2b)(a+3b)
=a^2+2a+1-(a^2+ab-6b^2)
=a^2+2a+1-a^2-ab+6b^2
=2a+1-ab+6b^2
=6b^2-ab+2a+1
=6b^2-a(b-2)+1