i) Find an equation for  l_2

Step 1: Calculate the slope of the given line equation

            NOTE: Putting the equation in the form y = mx (+c) and attempting to  

            extract the m

Step 2: Find the slope of the another line

            NOTE: i) Parallel lines have the same slope.

            ii) Perpendicular lines have slopes that are opposite reciprocals, like

             \frac{a}{b} \text{ and } \frac{-b}{a}. The slopes also have a product of -1

Step 3: Use the slope of line and a point on line to find its y - intercept.

            EXAMPLE: Plug the slope m = -2 and the point (-6, 4) into the

            slope-  intercept formula. Then solve for the y-intercept b.

            y = mx + b

            4 = -2(-6) + b

Step 4: Use the slope of line and the y-intercept of line to find the equation of the line.

            EXAMPLE: Plug the slope m = -2 and the y-intercept b = -8 into the

            slope- intercept formula.

                                      y = mx + b

                                      y = -2x + -8

ii) Find the coordinates of P, 

Step 1: Calculate the point by the given hints in the question

          NOTE: The point lies on the y-axis so the x-coordinate is zero

                        point p = (0, y)

Step 1: Substitute this point on the line equation and simplify you will get the unknown variable.