Step-by-step explanation:
If h is the number of hours Sally rented the bike then she paid 12 dollars fixed fee plus 9*h.
Which means that she paid 12+9*h.
However she paid 48 dollars which means:
[tex]12 + (9 \times h) = 48 \\ 9 \times h = 48 - 12 \\ 9 \times h = 36 \\ 9 \times h = 9 \times 4 \\ h = 4[/tex]
Which means that Sallly rented the bike for 4 hours
