Find the base please!!

Which of the following answers is 7/9 simplified? 7/9 2/9 11/9 2/7

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

Solve the equation -9p - 17 =10 a -3 b. 16 c. 18 d -16