If ^ n^2 - n C_2 = ^ n^2 - n C_ 10 , then n = - Vidyadip

MCQ

If $^{{n^2} - n}{C_2}{ = ^{{n^2} - n}}{C_{10}}$, then $n = $

A
$12$
B
$4$ only
C
$- 3$ only
✓
$4$ or $- 3$

✓

Answer

Correct option: D.

$4$ or $- 3$

d
(d) $^{{n^2} - n}{C_2}{ = ^{{n^2} - n}}{C_{10}}{ \Rightarrow ^{{n^2} - n}}{C_{{n^2} - n - 2}}{ = ^{{n^2} - n}}{C_{10}}$

$ \Rightarrow {n^2} - n - 2 = 10$ or $n = 4,\; - 3$.

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