Use the point-slope form: (y – y_1 = m(x – x_1))
Find the slope (m) using two points: (m = frac{y_2 – y_1}{x_2 – x_1})
Substitute the slope and one point into the point-slope form
Simplify to get the equation
If the line is horizontal, use (y = c)
If the line is vertical, use (x = c)
Use slope-intercept form if needed: (y = mx + b)
Find (b) by substituting a point into (y = mx + b)