As with any other kind of equation, graphing is a good tool. You can learn a lot from graphing, like approximate solutions (sometimes even exact), or qualitative information like the possible number of solutions. For example, since f(x) = b^x is monotone (either increasing if b>1, or decreasing if 0<b<1), the equation b^x = c can only have one solution (none if c is 0 or negative).