Prove that \(4+8\sqrt{19}\) is irrational
 
Proof:
 
Let us consider \(4+8\sqrt{19}\) is
 
\(4+8\sqrt{19}=\frac{p}{q}\) be a number, where \(p\) and \(q\) are and \(q\neq 0\)
 
\(8\sqrt{19}=\frac{p}{q}-\)
 
\(\sqrt{19}=\) pqii
 
Since, \(p\) and \(q\) are integers, pqii will also be number.
 
Therefore, \(\sqrt{19}\) is number.
 
This contradicts the fact that \(\sqrt{19}\) is number.
 
Hence, \(4+8\sqrt{19}\) is irrational number.