Question

Tìm x thuộc Z

a)2./x/+5=23

b)(x+5) (x-2) < 0

Kiểm tra dùm đê

Answer 1

\(2\left|x\right|+5=23\)

\(\Rightarrow2\left|x\right|=23-5=18\)

\(\Rightarrow\left|x\right|=\frac{18}{2}=9\)

Vậy: \(x\in\left\{9;-9\right\}\)

\(\left(x+5\right)\left(x-2\right)< 0\)

\(\Rightarrow\left[\begin{array}{nghiempt}x+5< 0\\x-2< 0\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x< 0-5\\x< 0+2\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x< -5\\x< 2\end{array}\right.\)

\(\Rightarrow-5< x< 2\)

Vậy: \(x\in\left\{-4;-3;-2;-1;0;1\right\}\)