Question

Do the three points lie on one line?

Answer 1

Answer:

Yes. No graph paper.

Step-by-step explanation:

Let's say the 3 points are A, B, C.

If A, B and C lie on one line then $m_{AB} = m_{BC} = m_{AC}$

$m_{AB} = \frac{y_{B}-y_{A} }{x_{B}-x_{A}} = \frac{2-6}{3-5} = \frac{-4}{-2} = 2\\m_{BC} = \frac{y_{C}-y_{B} }{x_{C}-x_{B}} = \frac{8-2}{6-3} = \frac{6}{3} = 2\\\\m_{AC} = \frac{y_{C}-y_{A} }{x_{C}-x_{A}} = \frac{8-6}{6-5} = \frac{2}{1} = 2$

Hence, they lie on one line.

You don't need to use a graph paper to prove it.