Question

. Let A = {x: x ϵ R, x2 – 5x + 6 = 0 } and B = { x: x ϵ R, x2 = 9}. Find A intersection B and A union B

Answer 1

$x^2 – 5x + 6 = 0\\x^2-2x-3x+6=0\\x(x-2)-3(x-2)=0\\(x-3)(x-2)=0\\x=3 \vee x=2\\A=\{-2,3\}\\\\x^2=9\\x=-3 \vee x=3\\B=\{-3,3\}\\\\A\cap B=\{3\}\\A\cup B=\{-3,-2,3\}$