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 .

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