Question

Prove that 4+2√5is irrational

Answer 1

Answer:

Since a, b are integers, then (a − 4b)/(−5b) represents a rational number. Hence our assumption that " 4−5√2 = (a/b) is a rational number" is incorrect. We know that RHS of this is Rational,but LHS is irrational. 4-5✓2 is irrational