In this lesson, students will learn how to multiply terms by using the distribution method and rules of exponents.
A monomial is an exponential expression that consists of one term with non-negative integer exponents—“mono” meaning “one.”
Following is an example of a monomial. In this term, 4 is the coefficient, x is the base, and 5 is the exponent.
A binomial is an expression that consists of two monomial terms—“bi” meaning “two.”
Here is an example of a binomial:
Lastly, a polynomial is an expression that consists of two or more monomial terms—“poly” meaning “many.”
Here is an example of a polynomial. Expressions should always be simplified by combining like terms if possible, so in this polynomial, you can combine the like terms 4a and 2a.
The distributive property is where the quantity that is outside of the parentheses is multiplied or distributed into every term inside the parentheses.
When multiplying a monomial by a binomial, the entire monomial is distributed, including the coefficients and the variable powers. Suppose you want to multiply:
Because your variable bases are the same, you can use the product property for exponents to add your exponents together when multiplying the variable powers together.
To multiply, you will use the distributive property to multiply 4m^3 by the terms within the parentheses. When you multiply 4m^3 by 5m^2 , you can use the commutative property of multiplication to rewrite the product by grouping your coefficients together and your variable powers together. Similarly, when you multiply 4m^3 by 2m, you can again use the commutative property of multiplication to rewrite your product.
To simplify your first term, multiply your coefficients, 4 and 5, which equals 20. Next, use the product property of exponents to add your exponents together.
Simplifying your second term, multiply your coefficients, 4 times 2, which equals 8. Note that your variable m has no written exponent, which means that it has an implied exponent of 1. Therefore, adding your exponents together provides:
Bringing your two terms back together, your final expression is in standard form because the term with the highest exponent power is written first, followed by the term with the next highest exponent power, and so on.
It is in standard form or descending order, so this is your final answer.
The same rules apply when multiplying monomials with polynomials. Consider the example below. You need to distribute the 3 on the outside of the parentheses to all three terms within the parentheses. Notice that the 3 does not have any variable bases or exponents, so you only need to multiply the coefficients. Also, remember that there is an implied -1 being multiplied by the b here.
Now you must reorder your terms so that they are in descending order, so you’ll need to switch the first and second terms to arrive at your final answer.
For this last example, you’ll need to multiply the term on the outside by each of the three terms inside the parentheses. Note that the outside term contains variables, coefficients, and exponents.
Begin by multiplying the outside term by the first term in the parentheses. 7 times 2 is 14, and you can also add the exponents of x^2 and x^5 because their bases are both x; y^3 stays unchanged. Next, multiply the outside term by your second and third term in the parentheses. Your expression is in standard form or descending order, so this is your final answer:
Source: This work is adapted from Sophia author Colleen Atakpu.
An exponential expression with non–negative integer exponents.
An expression containing two monomial terms.
An expression containing two or more monomial terms.