PLEASE ANSWER THIS!!!!!!!!

$\mbox{She works }90hr \mbox{ at her two jobs. }t \mbox{ is the time she works as a tutor.}\\ \mbox{so }90-t \mbox{ is the time she works as a waitress.}\\ \mbox{Multiplying these hrs by the salaries given you get.}\\ Total = 14 t + 15(90-t) = (1350-t)\$$

Let t be the number of hours Melissa worked as a tutor this month, then:

90 - t=number of hours Melissa worked as a waitress, therefore we have:

$14t + $15(90 - t)=expression for the combined total dollar amount she earned this month.