Please learn LaTeX, or at least use grouping symbols. For instance, in #2 is it supposed to be

or ?

I'll do the first, as it doesn't look ambiguous. To isolate the x, take the log base-2 of both sides:

If you need to state your answer as a decimal, use the change of base formula to change into either natural logs (base e) or common logs (base 10), and then plug into the calculator:

OR