Answer:
The equation is x + y = 15
Step-by-step explanation:
It is given that,
There are 15 plates and each plate is either 7 or 12 inches diameter.
Let the number of 7 inch plates be x and 12 inch plates be y
To find the equation
Total number of plates = 15
By using the given information, we can write
x + y = 15
Therefore the equation is x + y = 15