Question

\(\left|2x-3\right|\ge5\)

Giúp mk với

Answer 1

`|2x-3|>=5` 

Bình phương hai vế ta có:

`(2x-3)^2>=25`

`<=>(2x-3)^2-25>=0`

`<=>(2x-3-5)(2x-3+5)>=0`

`<=>(2x-8)(2x+2)>=0`

`<=>(x-4)(x+1)>=0`

`<=>` \(\left[ \begin{array}{l}\begin{cases}x-4 \ge 0\\x+1 \ge 0\\\end{cases}\\\begin{cases}x-4 \le 0\\x+1 \le 0\\\end{cases}\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}\begin{cases}x \ge 4\\x \ge -1\\\end{cases}\\\begin{cases}x \le 4\\x \le -1\\\end{cases}\end{array} \right.\) 

`<=>` \(\left[ \begin{array}{l}x \ge 4\\x \le -1\end{array} \right.\) 

Vậy...