How do I claim expenses from a previous year to offset income from rental arrears received this year?

My disabled daughter lives in my home and pays for room and board from SSI.  With deductions it's a wash and I don't owe any tax on it.  My issue is that her benefits were suspended for over a year due to an SSI error, and then reinstated with arrears paid from a previous year.  I understand that I have to declare the income from the arrears in the year I received them, but how can I claim expenses?  The expenses were in a previous tax year.