Question

If $A=\{x:x^2-3x+2=0\}$ and $R$ is a universal relation on $A,$ then $R$ is

• A. $\left\{\right(1,1),(2,2\left)\right\}$
• B. $\left\{\right(1,1\left)\right\}$
• C. $\left\{\varphi \right\}$
• D. $\left\{\right(1,1),(1,2),(2,1),(2,2\left)\right\}$

Answer 1

The correct option is D $\left\{\right(1,1),(1,2),(2,1),(2,2\left)\right\}$

$x^2-3x+2=0\Rightarrow (x-1)(x-2)=0\Rightarrow x=1,2\Rightarrow A=\{1,2\}\therefore A\times A=\left\{\right(1,1),(1,2),(2,1),(2,2\left)\right\}$