Finding and equation for a horizontal/vertical graph

[MathDumbo]

Hi guys,I need help on find an equation for these problems,here's how it looks like:

Write an equation for each line.Then graph the line.

38. through (-2,1) and parallel to y=-3x+1
39. through (-3,-1) and perpendicular to y=-2/5x-4
40. through (-7,10) and horizontal
41. through (1,-2/7)and vertical

Now the first two,I know how to do,but the second two are the ones I don't know how to do.Please help me.

Thanks in advance.

[stapel_eliz]

To learn the trick, try the two examples in the bottom half of this page.

Hint: One of the lines is of the form "y = (a number)" and the other is of the form "x = (a number)".

[nona.m.nona]

It helps to remember that vertical lines have no slope, so there won't be a "y" in the equation.