Question: prove that the square root of 5 is irrational?
Answer: In order to prove that square root of 5 is irrational, you need to understand also this important concept. ... 5 × y2 will then have an odd number of prime factors. The number 5 counts as 1 prime factor, so 1 + an even number of prime factors is an odd number of prime factors. 5 × y2 is the same number as x2.