Explanation:
LeChatlier's principle states that any  change in pressure, temperature, or concentration of a reactant applied to a system in equilibrium, the equilibrium will shift so as to tend to counteract the effect of the change.
In our question,[tex]AgCl[/tex] is added.
[tex]AgCl[/tex] is a product.
When product concentration increases,the reaction goes to the left so as to decrease the product concentration.