Did you receive a Form 1099-S setting forth the proceeds from the sale of the Texas house?
I assume you lived in the house 2 of the last 5 years.
If so, you will report the sale of the Texas house and be subject to tax on any gain that exceeds the exclusion amount ($250,000 if single or $500,000 if married filing joint).
The gain/loss equation is Proceeds minus Selling Expenses minus Basis equals Gain or Loss. Your basis is what you paid for the house plus your improvements added during your ownership.
Both the sale of the house in Texas and the purchase of the house in Maryland should have a Settlement Statement among the closing documents. Keep those documents. They may show Property Taxes and Mortgage Interest you paid in connection with each transaction. Also, the Texas Settlement Statement will set forth certain Selling Expenses you incurred.
