
# 10: Polynomials


Expressions known as polynomials are used widely in algebra. Applications of these expressions are essential to many careers, including economists, engineers, and scientists. In this chapter, we will find out what polynomials are and how to manipulate them through basic mathematical operations.

• 10.1: Add and Subtract Polynomials
In this section, we will work with polynomials that have only one variable in each term. The degree of a polynomial and the degree of its terms are determined by the exponents of the variable. Working with polynomials is easier when you list the terms in descending order of degrees. When a polynomial is written this way, it is said to be in standard form. Adding and subtracting polynomials can be thought of as just adding and subtracting like terms.
• 10.2: Use Multiplication Properties of Exponents (Part 1)
In this section, we will begin working with variable expressions containing exponents. Remember that an exponent indicates repeated multiplication of the same quantity. You have seen that when you combine like terms by adding and subtracting, you need to have the same base with the same exponent. But when you multiply and divide, the exponents may be different, and sometimes the bases may be different, too. We’ll derive the properties of exponents by looking for patterns in several examples.
• 10.3: Use Multiplication Properties of Exponents (Part 2)
All the exponent properties hold true for any real numbers, but right now we will only use whole number exponents. The product property of exponents allows us to multiply expressions with like bases by adding their exponents together. The power property of exponents states that to raise a power to a power, multiply the exponents. Finally, the product to a power property of exponents describes how raising a product to a power is accomplished by raising each factor to that power.
• 10.4: Multiply Polynomials (Part 1)
In this section, we will begin multiplying polynomials with degree one, two, and/or three. Just like there are different ways to represent multiplication of numbers, there are several methods that can be used to multiply a polynomial by another polynomial. The Distributive Property is the first method that you have already encountered and used to find the product of any two polynomials.
• 10.5: Multiply Polynomials (Part 2)
The FOIL method is usually the quickest method for multiplying two binomials, but it works only for binomials. When you multiply a binomial by a binomial you get four terms. Sometimes you can combine like terms to get a trinomial, but sometimes there are no like terms to combine. Another method that works for all polynomials is the Vertical Method. It is very much like the method you use to multiply whole numbers.
• 10.6: Divide Monomials (Part 1)
In this section, we will look at the exponent properties for division. A special case of the Quotient Property is when the exponents of the numerator and denominator are equal. It leads us to the definition of the zero exponent, which states that if a is a non-zero number, then a^0 = 1. Any nonzero number raised to the zero power is 1. The quotient to a power property of exponents states that to raise a fraction to a power, you raise the numerator and denominator to that power.
• 10.7: Divide Monomials (Part 2)
We have now seen all the properties of exponents. We'll use them to divide monomials. Later, you'll use them to divide polynomials. When we divide monomials with more than one variable, we write one fraction for each variable. Once you become familiar with the process and have practiced it step by step several times, you may be able to simplify a fraction in one step.
• 10.8: Integer Exponents and Scientific Notation (Part 1)
The negative exponent tells us to re-write the expression by taking the reciprocal of the base and then changing the sign of the exponent. Any expression that has negative exponents is not considered to be in simplest form. We will use the definition of a negative exponent and other properties of exponents to write an expression with only positive exponents.
• 10.9: Integer Exponents and Scientific Notation (Part 2)
When a number is written as a product of two numbers, where the first factor is a number greater than or equal to one but less than 10, and the second factor is a power of 10 written in exponential form, it is said to be in scientific notation. It is customary to use × as the multiplication sign, even though we avoid using this sign elsewhere in algebra. Scientific notation is a useful way of writing very large or very small numbers. It is used often in the sciences to make calculations easier.
• 10.E: Polynomials (Exercises)
• 10.S: Polynomials (Summary)
• 10.10: Introduction to Factoring Polynomials
Earlier we multiplied factors together to get a product. Now, we will be reversing this process; we will start with a product and then break it down into its factors. Splitting a product into factors is called factoring. In The Language of Algebra we factored numbers to find the least common multiple (LCM) of two or more numbers. Now we will factor expressions and find the greatest common factor of two or more expressions. The method we use is similar to what we used to find the LCM.

Figure 10.1 - The paths of rockets are calculated using polynomials. (credit: NASA, Public Domain)