Question

Consider the three points, (3,7),(-6,1) and (9,y) on the same line. Find the value of y and explain your steps.

Answer 1

let us find the slope using 2 points

`\begin{gathered} m=(y_2-y_1)/(x_2-x_1) \\ m=(1-7)/(-6-3) \\ m=(-6)/(-9) \\ m=(2)/(3) \end{gathered}`

Therefore let us find y

`\begin{gathered} (2)/(3)=(y-1)/(9+6) \\ (2)/(3)=(y-1)/(15) \\ \text{cross multiply} \\ 30=3(y-1) \\ 30=3y-3 \\ 33=3y \\ y=(33)/(3) \\ y=11 \end{gathered}`