. in 1997 i bought primary residence for 120k. in 2009 i was getting a new house, could not sell old one, so i opened line of credit for 200k under old house and used it as down payment for a new one. since that time since i could not sell old one, i had occasional renters, until finally was able to sell it now.outstanding loan was still 170k, sale price 250k. what is my capital gain? difference between initial purchase price in 1997 and selling price in 2018 or between outstanding balance and sell price?