What is the equation of the line containing the points (7, 3), (14, 6), and (21, 9)?

y = 3/7 x

Step-by-step explanation:

first we have to replace the value of the following formula with 2 points

m = (y2 - y1) / (x2 - x1)

m = (6 - 3) / (14 - 7)

m = 3 / 7

Now we are going to replace with the other point, to make sure that the 3 points belong to the function

y = mx + b

9 = 3/7 * 21 + b

9 = 9 + b

9 - 9 = b

0 = b

as b gave us zero it is not necessary to write the sum

y = 3/7 x

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0