2^x = 64 what is the solution

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

Ineed to know how to write question one in mathematical terms