$D=\left\{x\in R/\ x\ge-1\right\}=\left[-1,\ +\infty\right)$  

 $D=\left\{x\in R/\ x>-1\right\}=\left(-1,\ +\infty\right)$  

 $D=\left\{x\in R/\ x\le-1\right\}=\left(-\infty,-1\right]$  

 $D=\left\{x\in R/\ x<-1\right\}=\left(-\infty,-1\right)$  

D=R

 $D=\left\{x\in R/x\ne-1\right\}$  

 $D=\left\{x\in R/x\ne+1\right\}$  

 $D=\left\{x\in R/x\ne-1\wedge x\ne+1\right\}$