Question

Giải giúp mk bài này với ạ, mk cần gấp.Cảm ơn

Answer 1

b.

\(\Leftrightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}x< 2\\x>\dfrac{9}{2}\end{matrix}\right.\\-\dfrac{1}{3}< x< 7\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}-\dfrac{1}{3}< x< 2\\\dfrac{9}{2}< x< 7\end{matrix}\right.\)

Hay \(S=\left(-\dfrac{1}{3};2\right);\left(\dfrac{9}{2};7\right)\)

d.

\(\Leftrightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}x\le-\dfrac{11}{5}\\x\ge7\end{matrix}\right.\\-\dfrac{1}{2}< x< 3\end{matrix}\right.\) \(\Rightarrow x\in\varnothing\) hay BPT vô nghiệm