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Question Number 61860 by Tawa1 last updated on 10/Jun/19
$$\mathrm{simplify}:\:\:\:\:\overset{\mathrm{n}\:+\:\mathrm{1}} {\:}\mathrm{C}_{\mathrm{r}} \:−\:\overset{\mathrm{n}\:−\:\mathrm{1}} {\:}\mathrm{C}_{\mathrm{r}} \\ $$