[mandy9008]

CO(g) + Cl2(g)   COCl2(g)

initial concentrations:
[CO]=0.1550M
[Cl2]=0.177M

KP=255

what is equilibrium concentration of Cl2?
1.49*10-2K

now: i need to find the equilibrium concentration of Cl2.

this is my work:
x=85.66+-(square root)(85.662-4(255)(6.99))/2(255)
x=1.95

what to i do with this number?

[Astrokel]

x=85.66+-(square root)(85.662-4(255)(6.99))/2(255)
x=1.95

Explain your work?

Are you not given temperature?