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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

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827