Three fifths of a number is -54. what is the number?

Hello i need some with trigonometric substitutions. [tex]\int\limits^a_b {x} \, dx[/tex]

Ahome improvement store rents it’s delivery truck for $19 for the first 75 minutes and $4.75 for each additional 1/4 hour. if a customer rented the truck at 11: 10 am and returned the truck at 1: 40 pm the same day, what would his rental cost be?

Find the value of x for which the lines are parallel.