To represent the relationship between the price of a video game (p) and the price Mary would actually pay (d) after using a $10 coupon, we can write the equation as follows:
1. Let's denote the price Mary would actually pay as d and the original price of the video game as p.
2. The relationship can be expressed as: d = p - 10
3. In this equation, 'd' represents the price Mary would pay after using the $10 coupon, which is equal to the original price 'p' minus $10.
Therefore, the equation representing the relationship between the price of a video game (p) and the price Mary would actually pay (d) after using a $10 coupon is d = p - 10.