Question 332185
(xy-ab-6)-(xy-3ab-5)


Start by removing the brackets


xy - ab - 6 -xy +3ab +5


Note that two negatives makes a positive.


Now collect like terms:


xy - xy - ab + 3ab - 6 + 5


0 + 2ab - 1

= 2ab - 1


That's it. Hope that helps.