-2a(1/2b-1/2)+3b(b+1/3a)=

-2a(1/2b-1/2)+3b(b+1/3a)= -ab+a+3b²+ab= a+3b²

-2a(1/2b-1/2)+3b(b+1/3a)= -ab+a+3b²+ab=a+3b²

-2a(1/2b-1/2)+3b(b+1/3a)= -ab+a+3b²+ab = a+3b²