Step-by-step explanation:
x² +4ax+y² =0
x² +4ax+4a² +y² =4a²
(x+2a) ² +y² =4a² ......(i)
y² =4ax.........(ii)
By tracing the circle and the parabola we can clearly see that they touch each other along the y axis
So the equation of common tangent is x=0.
