A. x intercept is -8 ; y intercept is 4
Answer: The average was 9 years old find the average age of both groups is 10 years old.
Step-by-step explanation:
Formula foe average : 
Given : The first group of students consists of 10 and their average age was 13 years old.
i.e.
(1)
The next group consisted of 30 students and their average was 9 years old.
i.e.
(2)
Then from (1) and (2) , the sum of both groups (first group and next group )students = 130+270 =400
Combined students of both groups (first and next group )= 10+30=40
Now , the average of both groups =

Hence, the average was 9 years old find the average age of both groups is 10 years old.
Brand a costs less per load because b is more expensive per load
4 feet 6 inches
Step-by-step explanation:
P=2(l+w) [the addition of all sides of the rectangle]
P = 40'
L = 15’6”
So, 40' = 2 (15’6’ + w)
40' = 31’ + 2w
9' = 2w
4’6” = w
If it's easier you can break it change feet into inches and then change back to feet.
Write and solve an equation, as follows:
-7y + 5(3+ny) = 3y + 15. We are to find the value of 'n.'
-7y + 15 + 5ny = 3y + 15.
Subtracting 15 from both sides, we get -7y + 5ny = 3y
Grouping like terms, we get 5ny = 3y + 7y = 10y
Dividing both sides by 5y, we get n = 2 (answer)