Write down all the subsets of the following sets
$\{ a\} $
Which of the following are examples of the null set
$\{ y:y$ is a point common to any two parallellines $\} $
Make correct statements by filling in the symbols $\subset$ or $ \not\subset $ in the blank spaces:
$\{ x:x$ is a triangle in a plane $\} \ldots \{ x:x$ is a rectangle in the plane $\} $
Are the following pair of sets equal ? Give reasons.
$A = \{ 2,3\} ,\quad \,\,\,B = \{ x:x$ is solution of ${x^2} + 5x + 6 = 0\} $
Write the solution set of the equation ${x^2} + x - 2 = 0$ in roster form.