The expression
consists of ONE CONSTANT [180] and another VARIABLE EXPRESSION [15x].
Since the coach purchased ONE GOAL, this corresponds to the CONSTANT, which is 180. 180 is the price of the goal.
Since coach purchased several soccer balls, but doesn't say how many, it is the variable part, 15x, where
- either 15 is price of ball and x is the number of balls, OR
- 15 is the number of balls and x is the price of each
ANSWER:
180 represents the price of the goal
15x represents the total price of the soccer balls