Question

2. Tìm các số thực x thỏa mãn trị tuyệt đối 5x - 2 = trị tuyệt đối 7x - 3
 

Answer 1

mk đg cần gấp. TKS

 

Answer 2

x=1/2 hoặc x=5/12

 

Answer 3

`|5x-2|=|7x-3|`

Trường hợp 1 :

`5x-2=7x-3`

`<=>2x=1`

`<=>x=1/2`

Trường hợp 2 :

`5x-2=-(7x-3)`

`<=>5x-2=-7x+3`

`<=>12x=5`

`<=>x=5/12`

Vậy `S={1/2;5/12}`

Answer 4

Ta có: \(\left|5x-2\right|=\left|7x-3\right|\)

\(\Leftrightarrow\left[{}\begin{matrix}5x-2=7x-3\\5x-2=3-7x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}5x-7x=-3+2\\5x+7x=3+2\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}-2x=-1\\12x=5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=\dfrac{5}{12}\end{matrix}\right.\)