First you must acknowledge that you are dealing with a line therefore you must write linear equation or linear function in this case.
Linear function has a form of,
[tex]y=mx+n[/tex]
Then calculate the slope m using the coordinates of two points. Let say A(x1, y1) and B(x2, y2),
[tex]m=\dfrac{\Delta{y}}{\Delta{x}}=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
Now pick a point either A or B and insert coordinates of either one of them in the linear equation also insert the slope you just calculated, I will pick point A.
[tex]y_1=mx_1+n[/tex]
From here you solve the equation for n,
[tex]
y_1=mx_1+n\Longrightarrow n=y_1-mx_1
[/tex]
So you have slope m and variable n therefore you can write down the equation of the line,
[tex]f(x)=m_{slope}x+n_{variable}[/tex]
Hope this helps.
r3t40
