The equation that was used to solve the problem was:
2.50P + 1.25S = 696.25
This equation represents the total revenue made by selling pizza slices and sodas. The equation takes into account the price of each item and the total number of items sold.
The equation P + S = 384 was also used to represent the total number of items sold. This equation shows that the total number of pizza slices and sodas sold together is 384.
Therefore, to find the number of pizza slices and sodas sold separately, you must solve these two equations simultaneously using algebraic methods.