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For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

You can find the constant of proportionality by finding the ratio of

What are the solutions of the system? solve by graphing. y = -x^2 -6x - 7 y = 2