Select the correct answer from each drop-down menu. Robert is purchasing some equipment for his baseball team. He wants to buy some baseballs, each priced at m dollars. He has already spent b dollars on other equipment.

The following expression represents the total amount Robert will spend after buying x baseballs.

If the amount already spent by Robert on other equipment, b dollars, is doubled, then the value of m will
.

If the cost of each baseball, m dollars, is tripled, then the value of b will
and the value of mx will
.