Answer:
X = 3
Explanation:
I can't really draw the diagram for you.
$9 is always charged so just add that to the end of your equation.
x is what they charge for skates and their are 7 skates so 7x
$30 is the total
7x + 9 = 30
subtract 9 from both sides
7x = 21
divide by 7 on both sides
x = 3