I have no idea how to do this please I need answers

The following frequency table relates the weekly sales of bicycles at a given store over a 42-week period.value01234567frequency367108521(a) in how many weeks were at least 2 bikes sold? (b) in how many weeks were at least 5 bikes sold? (c) in how many weeks were an even number of bikes sold?

Is a positive integer raised to a negative power always positive

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?