Write an expression for the calculation divide 15 into thirds and subtract from 14 divided into half

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

What is the domain of the of the exponential function shown below?

The image of abc after a reflection across eg is abc