Question

√7 is irational no. ​

Answer 1

square root of 7 is irrational. As It cannot be expressed as a number in the form p/q 

Answer 2

Lets assume that √7 is rational number. ie √7=p/q. we divide by the common factor to get √7 = a/b were a and b are co-prime number. that is a and b have no common factor.