Let 3 – √5 is a rational number,we find out such integers numbers a and b (b ≠ 0)
3 – √5 = a/b
3 - a/b = √5
(3b - a)/b = √5
a and b are integer numbers
So, (3b - a)/b is a rational number.
So, √5 be also a rational number
But this fact is contradicted that √5 is an irrational number.
So our hypothesis is wrong.
3 – √5 is an irrational number.
