Is x + 2 a factor of x^20 - 4x^18 + 3x - 6 can't remember how to do this, explain how, i know it's really easy and simple

Use the remainder theorem to check.the remainder theorem says that for a binomial  , plugging  into a polynomial will get you the remainder of dividing  by  .when a binomial is a factor of a polynomial, dividing that polynomial by that binomial factor should have a remainder of zero.since we have  , it is  , so plug in x=-2 into the given polynomial    this basically says that if we divide  by  , we will get a remainder of -12.  therefore, x+2 is not a factor. the remainder needs to be zero for it to be a factor.