Question

Is 2-√5 is a rational or irrational number

Answer 1

irrational

let assume that

$2 - \sqrt{5}$

As rational number

$2 - \sqrt[]{5}$

=a/b

a and b are Co primes

after sending 2 on that side you will get

$\sqrt[]{5}$

equals a-2b/b

thus root 5 is rational bit a and b are integers

this contradicts the fact that

$2 - \sqrt[?]{5}$

irrational not rational