step 1. (((0-(4•(a2)))+3ab)+(12•(b2)))+(((9•(a2))+ab)-7b2)
step 2. (((0-(4•(a2)))+3ab)+(12•(b2)))+((32a2+ab)-7b2)
step 3.(((0-(4•(a2)))+3ab)+(22•3b2))+(9a2+ab-7b2)
step 4. (((0-(4•(a2)))+3ab)+(22•3b2))+(9a2+ab-7b2)
step 5. 5.1 Factoring 5a2 + 4ab + 5b2
