Keep in mind it won't cross the x-axis no matter what, since k is positive and the square bracket is positive (or 0), so it will look exactly the same for all values of k, just shifted up or down. The two 'points of interest' are the point where it crosses the y-axis and the bottom of the curve. The bottom of the curve is at x=-3, where the bracket is equal to 0, and the curve crosses the y axis at x=0, y=9+K.