250............................
You would subtract how many times Dion tagged bill with how many times bill tagged Dion, so 12 - 7 = 5
Answer:
<h3> 10,450</h3>
Step-by-step explanation:
21-13=8 and 29-21=8
So this is aritmetic series where a₁ = 13, and r = 8
Sum of the first n terms:

ah, those are systems you want one variable to cancel out. I would time the bottom equation by -1 so x cancels then u solve for y. then u plug all back in to solve for x.