PROVE THAT √13 is irrational. Hence, show that 5+ 3√13 is irrational. Share with your friends Share 0 Ankita Agarwal answered this Dear Student , Let us assume the contrary. i.e; 5+313 is rational ∴ 5+313= ab , where ‘a’ and ‘b’ are coprime integers and b ≠ 0313= ab – 5 313= a−5bb Or 13 = a−5b3b Because ‘a’ and ‘b’ are integers a−5b3b is rational That contradicts the fact that 13 is irrational. The contradiction is because of the incorrect assumption that (5 + 313) is rational. So, 5 + 313 is irrational. Regards 1 View Full Answer