Answer:
Thats not a full question
Step-by-step explanation:
Answer:
11 years old
Step-by-step explanation:
If four brothers have the average age 6, then the sum of their ages is

years.
Let x years be the age of sister. If four brothers and their sister have the average age 7, then

Multiply this equation by 5:

The sister is 11 years old.
Answer:
Part 1) 
Part 2) The equation satisfy the set of coordinates (see the explanation)
Step-by-step explanation:
step 1
Find the linear equation
The rule for the linear equation states that y is three more than twice x.
so
The variable y is equal to the number 2 multiplied by x plus the number 3

step 2
Prove that the equation satisfies the set of coordinates
substitute the value of x and the value of y in the linear equation and then compare the results
a) (-1, 1)

----> is true
so
The equation satisfy the ordered pair
b) (0, 3)

----> is true
so
The equation satisfy the ordered pair
c) (-1/3,7/3)

----> is true
so
The equation satisfy the ordered pair
therefore
The equation satisfy the set of coordinates