\(A\cap B=A\) ; \(B\cap C=B\)

\(\Rightarrow\left(A\cap B\right)\cup\left(B\cap C\right)=A\cup B=B\) (đáp án A đúng)

\(B\backslash C=\varnothing\Rightarrow A\cup\left(B\backslash C\right)=A\) (B cũng đúng)

\(A\backslash\left(B\cap C\right)=A\backslash B=\varnothing\) (C đúng)

Vậy D sai

\(\left(A\cap C\right)\cup B=A\cup B=B\) chứ ko phải C

E={0;1;2;3;4;5;6;7;8}

\(C_E^{A\cup B}=E\backslash\left(A\cup B\right)=E\backslash\left\{1;3;5;7;2;6\right\}=\left\{0;4\right\}\)

\(C_E^{A\cap B}=E\backslash\left\{1;3\right\}=\left\{0;2;4;5;6;7;8\right\}\)

=>\(C_E^{A\cup B}\subset C_E^{A\cap B}\)

a, \(A\subset B\Leftrightarrow\left\{{}\begin{matrix}m+3\ge5\\2m-1< -4\end{matrix}\right.\Rightarrow m\in\left\{\varnothing\right\}\)

b, \(B\subset A\Leftrightarrow\left\{{}\begin{matrix}m+3\le5\\2m-1>-4\end{matrix}\right.\Leftrightarrow-\dfrac{3}{2}< m\le2\)

c, \(A\cap B=\varnothing\Leftrightarrow\left[{}\begin{matrix}2m-1>5\\m+3\le-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}m>3\\m\le-7\end{matrix}\right.\)

d, \(A\cup B\) là một khoảng \(\Leftrightarrow\left\{{}\begin{matrix}m+3>5\\2m-1\le5\end{matrix}\right.\Leftrightarrow2< m\le3\)

​​​\(\left(A\cup C\right)\cap\left(B\cup D\right)\Rightarrow\left[{}\begin{matrix}x\in\left\{A;B\right\}\\x\in\left\{A;D\right\}\\x\in\left\{B;C\right\}\\x\in\left\{C;D\right\}\end{matrix}\right.\)​

\(\left(A\cup B\right)\cap\left(C\cup D\right)\Rightarrow\left[{}\begin{matrix}x\in\left\{A;C\right\}\\x\in\left\{A;D\right\}\\x\in\left\{B;C\right\}\\x\in\left\{B;D\right\}\end{matrix}\right.\)

Không rõ đề bài có đúng không nhỉ, có hai trường hợp không trùng nhau tức là VT khác VP.

a, \(X\in\left\{a;b\right\},\left\{a;b;c\right\},\left\{a;b;d\right\},\left\{a;b;e\right\},\left\{a;c;d\right\},\left\{a;c;e\right\},\left\{a;d;e\right\},\left\{a;b;c;d\right\},\left\{a;b;c;e\right\},\left\{a;c;d;e\right\},\left\{a;b;c;d;e\right\}\)

b,

\(X=\left\{3;4;5\right\}\)

c,đề có sai hay sao ý ạ

Chọn C