Predict the number of sales in month 5? asap

Which shows the pre image of triangle xyz

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

Describe the domain and range of y=2(3)^x-2+5