Question

prove 4-√5 is irrational

Answer 1

here is u r answer

Consider, 4−√5
Let 4−√5 = (a/b) a rational number 
⇒ −√5 = (a/b) − 4
⇒ −√5 = (a − 4b)/b
⇒ √5 = (a − 4b)/(−b)
Since a, b are integers, then (a − 4b)/(−b) represents a rational number.
But this is a contradiction since RHS is a rational number where as LHS (√5) is an irrational number
Hence our assumption that " 4−√5 = (a/b) is a rational number" is incorrect.
Thus  4−√5 is an irrational number 

hope u understand plz mark as brain list

Answer 2

it is correct answer mark it as brainlist one