Help plz (for savas realize)

Hillel is juggling flaming torches to raise money for charity. his initial appearance raises $500\$500 $500 , and he raises $15\$15 $15 for each minute of juggling performance. the amount rr r of money hillel raises is a function of tt t , the length of his performance in minutes. write the function's formula.

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?

This is so hard and it’s for a test