
This equation has the next form:

To find if the equation has two complex solutions we have to check if the discriminant is negative, as follows:

Then, the first case has two complex solutions.
In the second case,

The discriminant in this case is:

Then, the second case has two complex solutions.
In the third case,

The discriminant in this case is:

Then, the third case has two real solutions.
In the fourth case,

The discriminant in this case is:

Then, the fourth case has two complex solutions.