Answer:
+3
Step-by-step explanation:
Where the graph crosses the x axis is where the real zeros exist. The parabola's minimum is at point (-3,-3) by adding a +3 to the right side of the equation will raise the minimum to point (-3,0) therefore giving it only one point where it touches the x axis. Then the parabola will only have one zero, the minimum of the parabola.
