Consider a list of numbers which may have duplicate values. Write a python function to take a list as input, remove duplicates and output a list which does not have any duplicate values. Test your function on the following list [1,2,3,2,1,5,6,4,8,5, 4]. Consider two lists of numbers. Write a python function to take two lists as input and return True if there is at least one common number. Test your function on the two lists [10,20,30,40,50] and [40, 50,60, 70,80]. Write a python function to take a number n as input and output a dictionary that contains entries of the form (x,x*x) where x = 1,2, ..., n. Test your function on n = 10.