HOUSTON (AP) — Retail gasoline prices across Texas have slipped 2 cents this week. AAA Texas on Thursday reported the average price per gallon of regular unleaded settled at $3.51. That compares to the national average of $3.64 per gallon, which held steady this week. The association survey found Dallas and Fort Worth have the highest prices at the pump statewide at $3.59 per gallon. The cheapest gasoline in Texas was found in Beaumont at $3.38 per gallon. AAA Texas says retail gasoline prices declined steadily in March as oil prices crept higher on signs of continued economic recovery.