Answer:
Let's assume Pena's favorite number as "p".
According to the problem, Tonya's number is 9 more than Pena's favorite number, so Tonya's favorite number would be p + 9.
But Tonya says her favorite number is 44, so we can write:
p + 9 = 44
This equation represents the relationship between Pena's and Tonya's favorite numbers.