Examine whether the following statements are true or false :
$\{ a,b\} \not\subset \{ b,c,a\} $
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 $\} $
Let $A=\{a, e, i, o, u\}$ and $B=\{a, i, u\} .$ Show that $A \cup B=A$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{ \{ 3,4\} \} \subset A$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{ 3,4\} \in A$