What is the value of 6×7-3²×9+4³

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

It says factor each expression completely 8y+48

3x + 4y = 5 x- 3y = -7 solve by substitution