\(B=2\left|x+1\right|-\left|x-1\right|\)
- Nếu \(x\ge1\) thì : \(B=2.\left(x+1\right)-\left(x-1\right)=2x+2-x+1=x+3\)
- Nếu \(x=0\) thì :
\(B=2.\left(0+1\right)-\left(0-1\right)=2-\left(-1\right)=3\)
- Nếu \(x< 0\) thì :
\(B=2.\left(-x-1\right)-\left(-x+1\right)=-2x-2+x-1=-x-3\)