Typically, linear equations would be organized in slope-intercept form: y=mx+b where m is the slope and b is the y-intercept (the value of y when the line crosses the y-axis).
However, notice how the two x-coordinates of the given points are the same. They're both -3. This means that this is a vertical line, and vertical lines are organized in this equation: x=d where d is the x-intercept (the value of x when the line crosses the x-axis).
We know that the x-intercept is -3, since all the x-coordinates of the points that a vertical line passes through are the same. Therefore, the equation of this line is x=-3.
