Dividing Polynomials by Binomials With Example
Dividing a polynomial by a binomial means sharing the polynomial's terms between the two parts of the divisor. The most reliable school method is polynomial long division, done one term at a time.
The method, in order
1. Arrange both polynomials in descending powers of x. 2. Divide the first term of the dividend by the first term of the divisor. 3. Multiply the whole divisor by that result and subtract. 4. Bring down the next term and repeat until the remaining degree is smaller than the divisor's degree.
Worked example
Divide x² + 5x + 6 by (x + 2).
x² ÷ x = x. Multiply: x(x + 2) = x² + 2x. Subtract: (x² + 5x) − (x² + 2x) = 3x. Bring down 6. Then 3x ÷ x = 3. Multiply: 3(x + 2) = 3x + 6. Subtract and you get 0.
Answer: The quotient is x + 3, with remainder 0, so (x + 2) is a factor.
Check your answer
Multiply the quotient by the divisor and add the remainder. You should get back the original polynomial.
Learn more
For a video explanation of this topic, see Khan Academy Algebra course.
Related guides
Previous: What is Remainder Theorem? Formula with Example · Next: How to Factor Polynomials (With Examples) · All guides in this category