Help me please and thank you

Since the shape is a parallelogram, there are 2 pairs of opposite but equal sides --> "6a+21" and "20a+7"                   "11a" and "4a+7"

The easier pair is

11a = 4a+7              Subject 4a from both sides

7a = 7                     Divide 7 from both sides

a = 1

A = 1    

(2,20) means that the 2 is 2 hours and 20 is 20$. so there both 20$ for 2 hours only the same price. like it says. so, the dunk tank and the bounce house are the same price (20$) for the same amount of time (2 hours).

hope i