Why are eigenvalues real as well as complex?

Question

I have this $3\times 3$ matrix \begin{bmatrix} 5&2&3\\1&3&0\\ 1&0&1\end{bmatrix}

Its characteristic polynomial is $x^3-9x^2+18x-4$

Using Wolfram alpha the eigenvalues of the above matrix are coming as

https://www.wolframalpha.com/input/?i=%7B%7B5%2C2%2C3%7D%2C%7B1%2C3%2C0%7D%2C%7B1%2C0%2C1%7D%7D+eigenvalues

which are real numbers but when I am solving the characteristic polynomial given above I am getting it as complex numbers (see link below)

How can the roots be once complex and again real?

Can someone please explain the dilemma??

https://www.wolframalpha.com/input/?i=x%5E3%2Bx%5E2%28-9%29%2Bx%2818%29-4%3D0

Answer 1

It is a matter of notation in wolfram alpha. Try adding *:

x^3+x^2*(-9)+x*(18)-4=0.

You will see that now the roots match.

Answer 2

The solutions are indeed real numbers. In your wolfram alpha solution for characteristic polynomial, notice that $x$ appears on the right hand side as well.