This paper presents procedure to solve mutually dependent Fault Trees in success events expression. First, explain the basic procedure by using simple dependent fault trees. Next, the procedure is applied to more complex fault trees with 3 non-linear interrelated loops. FT structures are converted into a physical system model, which satisfy Boolean equations in success events expression. It is shown that the representative possible states of a physical system corresponding to mutually dependent Fault Trees can be obtained by formulary method. And FT with loops can be solvable without approximation.