Đáp án:
`x=65/8.`
Giải thích các bước giải:
`3x-|x+15|=5/4`
`=>3x-5/4=|x+15|`
Vì `|x+15|>=0`
`=>3x-5/4>=0`
`=>3x>=5/4`
`=>x>=5/12`
`=>` \(\left[ \begin{array}{l}3x-\dfrac54=x+15\\3x-\dfrac54=-x-15\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}2x=\dfrac{65}{4}\\4x=-\dfrac{55}{4}\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=\dfrac{65}{8}(TM)\\x=-\dfrac{55}{16}(KTM)\end{array} \right.\)
Vậy `x=65/8.`