What is the soultion set for the open sentence with the given replacement set? 15-x=9, {5,6,7,8}

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Solving algebraic equations 2m+3=11