Write the solution set of the equation ${x^2} + x - 2 = 0$ in roster form.
Which of the following are sets ? Justify your answer.
The collection of all natural numbers less than $100 .$
What universal set $(s)$ would you propose for each of the following :
The set of isosceles triangles
Write down all the subsets of the following sets
$\emptyset $
In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.
If $A \subset B$ and $B \in C,$ then $A \in C$