\(a,\left|x\right|=15-5=10\Leftrightarrow\orbr{\begin{cases}x=10\\x=-10\end{cases}}\)

\(b,\left|x-2\right|+3x=7\)

*)  Với x<2\(pt\Leftrightarrow2-x+3x=7\Leftrightarrow2x=5\Leftrightarrow x=\frac{5}{2}\)(loại )

*) Với \(x\ge2\Leftrightarrow x-2+3x=7\)\(\Leftrightarrow4x=9\Leftrightarrow x=\frac{9}{4}\)(thỏa mãn x>=2)

\(c,\left|x-1\right|+2x=6\)

*) Với x<1\(pt\Leftrightarrow1-x+2x=6\Leftrightarrow x=5\)(loại)

*) Với\(x\ge1\Leftrightarrow x-1+2x=6\Leftrightarrow3x=5\)\(\Leftrightarrow x=\frac{5}{3}\)(thỏa mãn x>=1)

\(\text{a)}\left|x\right|+5=15\)

\(\Rightarrow\left|x\right|=10\)

\(\Rightarrow x=10\text{ hay }x=-10\)

\(\text{b)}\left|x-2\right|+3x=7\)

\(\Rightarrow\left|x-2\right|=7-3x\)

\(\text{TH1:}x-2\ge0\Rightarrow x\ge2\)

\(\Rightarrow x-2=7-3x\)

\(\Rightarrow x+3x=7+2\)

\(\Rightarrow4x=9\)

\(\Rightarrow x=\frac{9}{4}\left(\text{Nhận}\right)\)

\(\text{TH2:}x-2< 0\Rightarrow x< 2\)

\(\Rightarrow x-2=-\left(7-3x\right)\)

\(\Rightarrow x-2=-7+3x\)

\(\Rightarrow x-3x=-7+2\)

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

\(\Rightarrow x=\frac{5}{2}\left(\text{Loại}\right)\)

Vậy \(x=\frac{9}{4}\)

\(\text{c)}\left|x-1\right|+2x=6\)

\(\Rightarrow\left|x-1\right|=6-2x\)

\(\text{TH1:}x-1\ge0\Rightarrow x\ge1\)

\(\Rightarrow x-1=6-2x\)

\(\Rightarrow x+2x=6+1\)

\(\Rightarrow3x=7\)

\(\Rightarrow x=\frac{7}{3}\left(\text{Nhận}\right)\)

\(\text{TH2:}x-2< 0\Rightarrow x< 2\)

\(\Rightarrow x-1=-\left(6-2x\right)\)

\(\Rightarrow x-1=-6+2x\)

\(\Rightarrow x-2x=-6+1\)

\(\Rightarrow-x=-5\)

\(\Rightarrow x=5\left(\text{loại}\right)\)

Vậy \(x=\frac{7}{3}\)

|x-7|+2x+5=6

=>   TH1:  x-7+2x+5=6 <=> 3x=8 <=> x=8/3

       TH2:  7-x+2x+5=6 <=> x+12=6 <=> x=-6

1.

$(x-6)(2x+10)>0$

$2x+10=2(x+5)$

$(x-6)(x+5)>0$

Hai nghiệm: $x=-5,\ x=6$

Tích dương khi:

$x<-5$ hoặc $x>6$

Vậy $x\in(-\infty;-5)\cup(6;+\infty)$.

2. $(2x-8)(x-2)<0$

$2(x-4)(x-2)<0$

$(x-4)(x-2)<0$

Hai nghiệm: $x=2,\ x=4$

Tích âm khi:

$2<x<4$

Vậy $x\in(2;4)$.

hơi khó

|x-7| hay (x-7)

Giá trị tuyệt đói ý :)