Can someone help with question 7 with inequalities

In the diagram, the measure of angle 9 is 85° which angle must also measure 85°?

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

Which function has the domain x> -11