How to define matrix with variable and solve the polynomial equation in the matrix?

Let,

A= [1 x²; 0 1], B= [1 0; 2x 1], C= [1 3x; 0 1]

Then,

[A]*[B]*[C] = [ 1+2x² 6x²+4x; 2x 6x²+1] = [Z]

I need to solve the polynomial equation from the resultant matrix

Z(1,2) = 6x²+4x=0

the roots of the polynomial at Z(1,2) is need to be known?

[Rik]

If you have the symbolic toolbox you should have plenty of tools to solve this equation.

[Vinothkumar Sethurasu]

Thank you.