Please help! I will give as many points as I can!!

The administrator of a large assisted living facility wanted to know the average age of the residents living at the facility. he randomly selected 12 residents and determined their age, listed here: 80, 65, 75, 83, 68, 73, 88, 79, 94, 72, 79, 68 what's the average age of the sample of residents? a. 79 years old b. 68 years old c. 75 years old d. 77 years old

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

Which shows the correct substitution of the values a, b and c from the equation 1=-2x+3x^2+1