Question

Prove that 3√5 is irrational

Answer 1

3√5=a/b
√5=a/3b{since a and b r integers
√5=a/3b is rational}
therefore√5 is rational
but we have proved above that √5 is irrational
so,our assumption is wrong
3√5is irrational

Answer 2

hey!


here is answer

to prove

$3 \sqrt{5} is \: irrational$


$let \: 3\sqrt{5} \: be \: a \: rational \: no$

then

$3 \sqrt{5} = \frac{a}{b} \: where \: a \: and \: b \: are \: integer$

and b≠0

$3 \sqrt{5} = \frac{a}{b}$

$\sqrt{5} = \frac{a}{3b}$


here a/3b is rational number but
$\sqrt{5}$
is irrational number.

hence the. contradiction we suppose is. wrong

$hence \: 3 \sqrt{5} is \: irrational \: no$


hope it helps

thanks