Question

2 root 5 is an irrational number

Answer 1

root 5 is an irrational number.
so,2root 5 us an irrational Number

Answer 2

$Hey\:there$ ‼
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Let 2√5 be rational number.

2√5 = a / b , where a and b are co-prime and (b≠0)

√5 = a / 2b

Since, a / 2b is rational so, √5 is also rational.

But this contradicts the fact that √5 is irrational.
Therefore, our incorrect consumption is wrong.

So, we conclude that 2√5 is an irrational number.
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$Hope\: my \: ans.'s \: satisfactory.$