Q4 of 118 Page 17

Write the expression in the simplest form.

nCr+1 + nCr-1 + 2 nCr


= (nCr+1 + nCr) + (nCr + nCr-1)


⇒ (nCr + nCr-1 = n+1Cr)


= n+1Cr+1 + n+1Cr


⇒ (nCr + nCr-1 = n+1Cr)


= n+2Cr+1


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