2 + 5 , 1 are roots of the cubic equation given by

Step-by-step solution

We know that, in a cubic equation with rational coefficients has a irrational root α + β , where α and β are rational and β is not a perfect square, then it has also a conjugate root α - β . Hence, 1 ,   2 + 5 ,   2 - 5 are the roots of cubic equation. We know that, if α ,   β ,   γ are the roots of cubic equation, then its equation is x 3 - α + β + γ x 2 + α β + α γ + β γ x - α β γ . Le