Alinear function that represents the number of video games purchased at an electronics store is compared to a different linear function that represents the amount of money the store made that day describe the key features of the function that are needed to determine if these lines intersect

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