[tex]\sqrt{5}[/tex] is irrational
A rational number can be expressed in the form
[tex]\frac{a}{b}[/tex] where a, b ∈ Z ( integers )
[tex]\frac{-9}{5}[/tex] is in this form → rational
[tex]\sqrt{5}[/tex] cannot be expressed in this form → irrational
[tex]\frac{7}{3}[/tex] is in this form → rational
[tex]\sqrt{9}[/tex] = ± 3 and [tex]\frac{3}{1}[/tex], - [tex]\frac{3}{1}[/tex] → rational
