Preliminary future speakers: A. Miasnikov, V. Remeslennikov, A. Treyer.We show that the power word problem for a solvable Baumslag-Solitar groups BS(1,q) belongs to the circuit complexity class TC0; a very small complexity class within polynomial time (even logspace). The power word problem is a succinct version of the classical word problem, where the input consists of group elements g_1,…, g_d (encoded as words over a set of generators) and binary encoded integers z_1,..., z_d and it is asked whether g_1^{n_1} ... g_d^{n_d} = 1 holds in the underlying group. Moreover, we prove that the knapsack problem for BS(1,q) is NP-complete. In the knapsack problem, the input consists of group elements g_1,…, g_d, h, and it is asked whether the equation g_1^{x_1} ... g_d^{x_d} = h (where the x_i are variables ranging over the natural numbers) has a solution.