-3(2d)+ (-5e +6) + (3d-8) I'm standard form

Aregular pentagon with a perimeter of 21 inches is dilated by a scale factor of 5/3 to create a new pentagon. what is the perimeter of the new pentagon?

Suppose a store sells an average of 80 cases of soda per day. assume that each case contains 24 cans of soda and that the store is open 10 hours per day. find the average number of soda that the store sells per hour.

What is the solution to this system of equations? y= 2x - 3.5 x - 2y = -14