The set $A = \{ x:x \in R,\,{x^2} = 16$ and $2x = 6\} $ equals
$\phi $
$\{14, 3, 4\}$
$\{3\}$
$\{4\}$
Write the following sets in roster form :
$B = \{ x:x$ is a natural number less than ${\rm{ }}6\} $
Write the set $\{ x:x$ is a positive integer and ${x^2} < 40\} $ in the roster form.
Write the solution set of the equation ${x^2} + x - 2 = 0$ in roster form.
Write the set $A = \{ 1,4,9,16,25, \ldots .\} $ in set-builder form.
Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?