At 250 degrees C, the reaction: has an equilibrium constant K c = 1.80. If 0.200 mol of PCl 5 is placed in a 5.00 L container, what will be the

At 250 degrees C, the reaction:

has an equilibrium constant Kc= 1.80. If 0.200 mol of PCl5 is placed in a 5.00 L container, what will be the equilibrium concentration of Cl2?

I understand how to form the ICE chart, my brain is dead and I'm not understanding the next step of how to solve the below equation through a calculator of:

1.80= x2/0.04-x