Since you have to roots, you can write the equation as $(x-(3-\sqrt{2}))*(x-(1+2\sqrt{2}) = 0$ Multiplying the terms $x^2 - x * (1+2\sqrt{2}) - x * (3-\sqrt{2}) - ((3-\sqrt{2})*(1+2\sqrt{2})) = 0$ Simplify the terms and you have your answer.