State which of the following sets are null set or singleton set:the set of real roots of `x + 1 = 0`

State which of the following sets are null set or singleton set:the set of even prime numbers

State which of the following sets are null set or singleton set:the set of Indian medalists in 1996 Olympic

State which of the following sets are null set or singleton set: the set of natural numbers less than 1

State which of the following sets are null set or singleton set:the set of deserts in the Himalayan range

State which of the following sets are null set or singleton set:the set of positive odd integers less than 3

State whether the following sets are null set or singleton set: {x|x in R,x!=x}

State whether the following sets are null set or singleton set: {x|x in R,x^2=-4}

State whether the following sets are null set or singleton set:the set of prime numbers divisible by 6

State whether the following sets are null set or singleton set: {x|x in R,x=root(3)(1)}

Express the following sets in roster method : the set of real roots of x^2 -25 = 0