Question

6) The three points (15, 189), (9, 111) and (-7, y) are all on the

same line. What is the value of y in the final ordered pair?

Answer 1

Explanation:

If it's on the same line, that means that the slope from each point to the other must be the same.

Using the first given points, we can calculate the slope to be:

`m = (189-111)/(15-9)=(78)/(6)=13\\`

We can solve for y

`13 = (111-y)/(9--7)\\13=(111-y)/(16)\\111 - y = 208\\y = -97\\`

We can double check:

`m = (111--97)/(9--7)\\m=(208)/(16)=13`