Saving on capital gains tax

Hello,

 

I wanted to find out if there is a way for me to reduce what I will owe on capital gains tax. I borrowed funds from a bank line of credit to purchase half of a condo for my mother; she owns the other half. I paid interest on the line of credit and she lived in the condo as her primary residence (meaning it was never rented out). We have sold it now and since I live in my own primary residence I realize that I need to pay capital gains on the appreciation. Is there any deduction I can take, or is there some way that I can reduce, to lower how much capital gains I need to pay? I am retired.

 

Thank you