Given: Two roots are 2+√5and2−√5 . Concept used: The quadratic equation is: x2 - (Sum of roots)x + Product of roots = 0 Calculation: Let the roots of the equation be A and B. A = 2+√5andB=2−√5 ⇒ A + B = 2+√5+2−√5=4 ⇒ A × B = (2+√5)(2−√5)=4−5=−1 Then equation is ∴ x2−4x−1=0