Two pools are being filled with water. To start, the first pool had liters of water and the second pool has liters of water. Water is being added to the first pool at a rate of liters per minute. Water is being added to the second pool at a rate of liters per minute. Let be the number of minutes water has been added. (a) For each pool, write an expression for the amount of water in the pool after minutes. (b) Write an equation to show that the two pools have the same amount of water.