Find the equation of the line that contains the point whose coordinates are (3, 1) and has a slope of 3.

slope  =  (y₂ - y₁) / (x₂ - x₁)

 

Using the points  (3, 1)  and  (x, y)  and a slope of  3 , we get

 

3  =  (y - 1) / (x - 3)       To get it in slope-intercept form, multiply both sides by  (x - 3) .

 

3(x - 3)  =  y - 1

 

3x - 9  =  y - 1              Add  1  to both sides.

 

3x - 8  =  y

 

y  =  3x - 8