Please, please, post only ONE question at a time. Â The way Brainly is set up, it's very difficult to conclude one problem and then move on to the next in the same session.
Solve y = log3243. Â I must make the assumption here that you mean:
Solve y = (log to the base 3) of 243.
Solve y = (log  243  in better, more compact form.
           3
If you recognize that 243 is an integer power of 3, the problem becomes much easier. Â
         2       3       4          5
Note that 3 Â = 9, Â Â 3 Â = 27, 3 Â =81, and 3 Â = 243.
Also note that the log function and the exponential function are inverses of one another, and that inverse functions "undo" each other.
           x
Thus, log   3   is simply x.
        3
                      5
Thus, log   243  =  log   3   = 5 (answer).
        3          3
Please repost the rest of your questions, one at a time, and then I will gladly help you with them.