Devon purchased tickets to an air show for 9 adults and 2 children. the total cost was $206. the cost of a childs ticket was $7 less than the cost of an adults ticket. find the price of an adults ticket and a childs ticket.

Ledt n= adult price
Let n-7= child's price  ($7 less than adult price)

9n + 2(n-7)= $206  (9 adult tix + 2 child tix = $206)
9n + 2n -14 = $206  I distributed the 2 over the n-7
11n - 14 = $206   I combined the 9n and 2n
11n = $220  I added 14 to both sides
Now divide both sides by 11 to get n alone.  $220 ÷ 11 = $20
n= $20  so the adult tickets cost $20 each  and the childrens are $7 less or $13
each
Let's check 9 adults at $20 each = $180 and 2 children @ $13 each is $26
$180 + $26 = $206