Question: prove that 3 by 2 root 5 is irrational?
Answer: So 3+2√5 = a/b where a,b are integers and are co primes and b is not equal to 0. ... In this since,b,3,2 are integers a-3b and 2b are integers and 2b is not equat to 0. So it is a fraction of integers. => √5 is rational which is a contradiction since √5 is irrational.