(c) Given $B^{r} = I \Rightarrow B^{r}B^{- 1} = IB^{- 1} \Rightarrow B^{r - 1} = B^{- 1}$ $\Rightarrow A^{- 1}B^{r - 1}A - A^{- 1}B^{- 1}A = A^{- 1}B^{- 1}A - A^{- 1}B^{- 1}A = 0$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.