We want to draw the graph of the given function, which has the form y=x2+k, where k is either a positive or a negative number. y=x2−9 To do so, we will first draw the graph of its parent function, y=x2. Recall that the graph of y=x2 is a parabola opening upwards, with vertex (0,0), whose axis of symmetry is the vertical line x=0, and passes through the points (3,9) and (-3,9).
Our function is a vertical translation of the parent function by 9 units in the negative direction. Thus, we will translate the above graph 9 units downwards.