(1) 5(3a-2b)+4(2b-3a)
=15a-20b+8b-12a
=3a-12b
(2) 1/3(a+2b)+1/4(3a-2b)-1/2(a-b)
=1/3a+2/3b+3/4a-1/2b-1/2a+1/2b
=7/12a+2/3