Question

Given $A=\{x|x$ is a root of $x^2-1=0\}B=\{x|x$ is a root of $x^2-2x+1=0\}$. Then

• A. $A\cap B=A$
• B. $A\cup B=\varphi$
• C. $A\cup B=A$
• D. $A\cap B=\varphi$

Answer 1

Answer: (C)

$A=\{1,-1\},B=\{1\}.\therefore A\cup B=\{1,-1\}=A$.