Jack's method is equivalent because of the "law of commutative property", which means that multiplication problems have the same result no matter the order.
Point-slope form is y - y1 = m(x - x1). We just need to plug in our stuff. This gives us y - 9 = 4(x - 3). I am not sure if you need to simplify, but if you do, y - 9 = 4x - 12.
