If a polynomial P(x) is divided by x - a until the remainder R does not contain x, then R = P(a)
P(x) = (x-a)Q(x) + R
Where P(x) is the polynomial expression
(x-a) is the expression being divided into the polynomial
Q(x) is the Quotient (the result of the algebraic division)
R is the remainder (of the algebraic division)
This can be used to:
Where there is no remainder, this can be used (as factor theorem) to determine the factors of a polynomial expression.