Question

nC2=nC10 then n = _______​

Answer 1

Answer:

$\huge\star\underline{\orange{❥︎a}\mathfrak\blue{n}\mathfrak\purple{S}\mathbb\pink{wer}}\star\:$

We have 

n2−nC2=n2−nC10

We know that

nCx=nCy⇒x=y or x+y=n

⇒2+10=n2−n

⇒n2−n=12

⇒n2−n−12=0

⇒n2−4n+3n−12

⇒n(n−4)+3(n−4)=0

⇒(n+3)(n−4)=0

⇒n=4, −3

So, n=4  [n is non negative integer]

Answer 2

Given,

Given,n2−nC2=n2−nC10

We know that,

nCx=nCy

⇒x=y or x+y=n

⇒2+10=n2−n

⇒n2−n=12

⇒n2−n−12=0

⇒n2−4n+3n−12

⇒n(n−4)+3(n−4)=0

⇒(n+3)(n−4)=0

⇒n=4, −3

So, n=4  [n is non negative integer]