Prove why ABX CDX are similar

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

Ineeeeed this is due tomorrow and i dont know the answer can you find all the exponents

It says factor each expression 49x-28?