There are 3 possible cases.

Case 1:

If it's positive, we can say that which doesn't have a root.

Case 2:

It's negative, we can rewrite it as

--! We found a root

Case 3:

For , so we don't have roots in this region.

Conclusion: The equation has only the root .

Graph:

We can rewrite the equation as and plot this function.

See where this graph crosses the x axis.