Question

prove 5√2 is an irrational

Answer 1

let a be a rational no.
a=5√2
a/5=√2
a is a rational number,5 is a rational number
a/5 is a rational number
√2 is a rational number
but wkt √2 is an irrational number
this contradicts the fact that our assumption is right
therefore 5√2 is an irrational number