Question

Prove 3√6+3 as irrational number.

Answer 1

let 3√6+3 be rational 
then 3√6+3 = a/b
3√6=a/b-3
√6=a/3b-9b/3b*1/3
√6 is irrational and RHS is rational 
hence our assumption is wrong
hence 3√6 +3 is irrational