Answer:
<em>Riley has 72 tokens</em>
Step-by-step explanation:
<u>System of Equations
</u>
We have two conditions for the tokens Riley and Erik have earned. Let's call x and y to the number of tokens of Riley and Erik respectively. The first condition states that

Solving for y

The second condition is that the ratio of the number of tokens that Riley had to the number of tokens that Erik has is 8 to 7. It's written as

Or equivalently

Replacing y from the first equation

Operating

Simplifying


Riley has 72 tokens
For the expression

, the coefficient of the x² term is 1.
Go to a math calculator and type this in then press graph and it will give you your answer