Find all values of the missing digit that make the statement true 214,21_ is divisible by 11

Answer 1

A number divisible by 11 has the property that the sum of even digits minus the sum of odd digits is 0 or divisible by 11.
14641 is divisible by 11 because
(4+4)-(1+6+1)=0
So if the missing digit is x, and if the number 21321x is divisible by 11, then
(1+2+x)-(2+3+1)=0
solve for x.

Answer 2

I am not following. The number you placed x in you used the number 21321x, but the number is 21421x. I am not following your steps to solve for x either

Answer 3

Sorry, it was a typo. My apologies.
For 21421X
So if the missing digit is x, and if the number 21421x is divisible by 11, then
(1+2+x)-(2+4+1)=0
solve for x.