6. A state 7 is said to be reachable in k steps if there is a sequence of inputs u[0],..., u[k 1] such that x[k] = 7. Show that if is reachable in k steps, then it is reachable in k +1 steps. 6. A state 7 is said to be reachable in k steps if there is a sequence of inputs u[0],..., u[k 1] such that x[k] = 7. Show that if is reachable in k steps, then it is reachable in k +1 steps