What is the simplified from of 7(5x - 6)

Which ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

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

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!