Answer:
84*(1/4)^x
Explanation:
84 is the constant as it is the starting amount. However each round (x because the amount of rounds is constantly changing) divides the team by 4 or multiplies by 1/4 (Reciprocal).
So, if you wanted to see if the amount of teams after three rounds you would do:
84 * 1/4 * 1/4 * 1/4. However, any number times itself is an exponent, so we would simplify to 84³. But due to the fact we do not know how many rounds we are going to calculate we change the exponent to x.