If the highest degree of an equation is 3, then the equation must have 3 solutions. Solutions can be: 1) 3 real solutions 2) one real and two imaginary solutions.
The quadratic equation will have two solutions.
There is one and only one real solution, and no imaginary solutions, of the equation x13 = 1. The solution is x = 1. If x = -1 then x13 = -1, so that does not work. If x = i, then x13 = -i, so that does not work. If x = -i, then x13 = -i, so that does not work.
As many solutions as there are points in the domain.
It has infinitely many solutions.
0 = 0 is an identity and not an equation. Equations have solutions, identities do not.
0 real solutions. There are other solutions in the complex planes (with i, the imaginary number), but there are no real solutions.
Is a trigonometric equation which has infinitely many real solutions.