Help looks like i forgot to read a ruler

On a architect's drawing of a house, 1 inche representa 1.5

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

Find the zero function by factoring (try to show work) h(x)=-x^2-6x-9