2 câu trả lời
\[\begin{array}{l} y = 5 - 2\sin x\\ Ta\,\,co:\,\, - 1 \le \sin x \le 1\\ \Rightarrow - 2 \le - 2\sin x \le 2\\ \Leftrightarrow 3 \le 5 - 2\sin x \le 7\\ \Rightarrow \left\{ \begin{array}{l} Min\,y = 3\,\,\,khi\,\,\,\sin x = 1\\ Max\,\,y = 7\,\,khi\,\,\,\sin x = - 1 \end{array} \right.. \end{array}\]
