X={a;b;0;1;2}, Y = {x ∉ N* :x^4 -3x² +2 =0 Chọn khẳng định đúng? A. X ∪ Y =X B. X ∪ Y =Y C. X \ Y = ∅ D. X ∩ Y = ∅

\[\begin{array}{l} X = \left\{ {a;\,\,b;\,\,0;\,\,1;\,\,2} \right\};\,\,\,Y = \left\{ {x \notin N*:\,\,\,{x^4} - 3{x^2} + 2 = 0} \right\}\\ {x^4} - 3{x^2} + 2 = 0 \Leftrightarrow \left[ \begin{array}{l} {x^2} = 2\\ {x^2} = 1 \end{array} \right. \Leftrightarrow \left[ \begin{array}{l} x = \sqrt 2 \\ x = - \sqrt 2 \\ x = - 1\\ x = 1 \end{array} \right.\\ \Rightarrow Y = \left\{ { - \sqrt 2 ;\,\,\sqrt 2 } \right\}.\\ \Rightarrow X \cap Y = \emptyset .\\ \Rightarrow Chon\,\,\,D. \end{array}\]