Mike D. answered 07/28/20
Effective, patient, empathic, math and science tutor
Jade
Well if a polynomial P(x) has three roots a, b, c then P(x) = (x-a) (x-b) (x-c)
So all you have to do here is expand (x-4-√2) (x-4+√2) (x-2).
(Multiply the first two brackets together. There will be 9 terms. The terms with √ will cancel out giving a quadratic with integral coefficients and leading coefficient 1. Then multiply this by (x-2)).
Mike