Write a system of equations to describe the situation below, solve using substitution, and fill
in the blanks.
Zach is going to the water slides and needs to figure out which deal is better. He can pay $39
to go on the water slides as much as he wants, or he can pay $17 to get in, plus an additional
$1 per trip down the water slides. If Zach goes on a certain number of trips down the water
slides, the two options are equivalent in terms of cost. How many trips is that? What is the
cost?