The correct answer is Choice A.
This is an example of an exponential equation, so we need the formula

.
The a value is the starting value of 100. The b value must be a decimal lower than 1 because it is decreases.
If you substitute in 8 for x, you will see that the output is about 50 (half of 100).
7.
a. This is an equation because it has to parts, separated by an equal sign
b. 5 because 5 is the number b is multiplied by in the first part
c. idk
d. a, b, and c are the variables
e. idk
sorry haven't done this in a while
2 out of 8 people sharing the prize is 2/8 or 25% of the people sharing the prize