Tập nghiệm của bất phương trình 

B

- Hướng dẫn giải

$\sqrt{x^2-x}>x+1\iff [\begin{array}{c}\left\{\begin{array}{l}x+1<0\\ x^2-x\ge 0\end{array}\right.\\ \left\{\begin{array}{l}x+1\ge 0\\ x^2-x>0\end{array}\right.\end{array}\iff [\begin{array}{c}\left\{\begin{array}{c}x<-1\\ [\begin{array}{l}x\ge 1\\ x\le 0\end{array}\end{array}\right.\\ \left\{\begin{array}{l}x\ge -1\\ x^2-x>x^2+2x+1\end{array}\right.\end{array}$

$[\begin{array}{c}x<-1\\ \left\{\begin{array}{l}x\ge -1\\ -3x>1\end{array}\right.\end{array}\iff [\begin{array}{c}x<-1\\ \left\{\begin{array}{l}x\ge -1\\ x<\frac{-1}{3}\end{array}\right.\end{array}\iff [\begin{array}{l}x<-1\\ -1\le x\le \frac{-1}{3}\end{array}\iff x<\frac{-1}{3}$

Chọn B.