Question

Help me please with this math , I don’t get it .

Answer 1

Given two points, we can find the equation of a line using the following formula

`\begin{gathered} (x_1,y_1),(x_2,y_2)\to\text{ two points on the line} \\ y-y_1=(y_2-y_1)/(x_2-x_1)(x-x_1) \end{gathered}`

In our case,

`\begin{gathered} (2,1),(9,9) \\ \Rightarrow y-1=(9-1)/(9-2)(x-2) \\ \Rightarrow y-1=(8)/(7)(x-2) \\ \Rightarrow y=(8)/(7)x-(16)/(7)+1 \\ \Rightarrow y=(8)/(7)x-(9)/(7) \end{gathered}`

The answer is y=8x/7-9/7