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| 11 Theory slides |
| 10 Exercises - Grade E - A |
| Each lesson is meant to take 1-2 classroom sessions |
Here are a few recommended readings before getting started with this lesson.
A monomial is an algebraic expression consisting of only one term. It is a product of powers of variables and a constant called the coefficient.
A single-term expression is a monomial only if all of its variables have whole numbers — non-negative and integers — as exponents. However, variables with positive exponents in the denominator are excluded because they are equivalent to a power in the numerator with the opposite exponent, according to the Quotient of Powers Property. Consider the following example. 5x/y^2 = 5xy^(- 2) In other words, if a variable in the denominator of an expression, it is not a monomial. The following are valid examples of monomials.
Expression | Why It Is a Monomial |
---|---|
5 | Any constant is a valid monomial. By the Zero Exponent Property, 5x^0=5. |
0 | The coefficient of a monomial can be 0. |
- 2x^5 | The coefficient can be negative. |
x^3y/5 | A monomial can have numbers in the denominator. |
Although they appear to be monomials at first glance, the single-term expressions in the following table do not satisfy the definition of a monomial.
Expression | Why It Is Not a Monomial |
---|---|
2x^(- 1) | The variables of a monomial cannot have negative integer exponents. |
4x^3/y | Monomials cannot have variables in the denominator. |
5 x^3y^(12) | The variables of a monomial must only have whole number exponents. |
Determine whether the given expression is a monomial.
The degree of a monomial is the sum of the exponents of its variable factors. If a variable has no exponent written in it, it is assumed to be 1. Additionally, all nonzero constants have a degree of 0. The constant 0 does not have a degree.
Monomial | Degree |
---|---|
3x | 1 |
x^2 | 2 |
9x^3 | 3 |
x^3y | 4 |
7 | 0 |
a^3b^4c^5/13 | 12 |
0 | undefined |
Determine whether the given monomial is a linear expression.
Diego is having friends over this evening to watch movies and hang out. It would be great if they had some snacks while watching the movies! He suddenly remembers that he has a coupon in his wallet.
This coupon gives him 5 % off when buying snacks! Diego uses x to represent the total cost of the snacks he will buy. When he uses the coupon, 5 % of the sales price will be discounted from this total. x-0.05x=0.95x This means that Diego will only pay 95 % of the total.
0.95x The variable is x and the coefficient is 0.95. The variable x represents the normal price of the snacks Diego wants to buy. The coefficient 0.95 represents the total after a 5 % discount.
The only operation involved in this expression is the multiplication of the variable and the coefficient, so this expression is a monomial.
A monomial whose degree is 1 is a linear expression. Another linear expression can be created by either adding or subtracting a constant from a monomial of degree 1.
Start by finding the GCF of the linear expression. Rewrite each term as the product of its factors. 12x &= 2* 2 * 3 * x 4 &= 2* 2 The GCF of the initial expression is 2* 2= 4.
Next, rewrite each term of the initial expression as the product of the GCF and another factor. 12x &= 4* 3x 4 &= 4* 1 Now write the initial expression as follows. 12x+4 ⇕ [0.25em] 4* 3x+ 4* 1
Finally, use the Distributive Property to factor out the GCF. 4* 3x+ 4* 1 ⇕ [0.25em] 4( 3x + 1 ) The expression between the parentheses can to be examined to determine whether it is possible to continue the factorization. Here, the terms do not have any more common factors, so the linear expression is completely factored.
After grabbing the snacks for his get-together, Diego saw that the store had a sale on fruit.
Find the common factors of each term.
Consider the given linear expression and identify greatest common factor (GCF) of the terms.
The challenge presented at the start of the lesson can be solved by using the methods learned in this chapter. Consider the given linear expression. 18x+15 Begin by finding the factors of 18x and 15. 18x &= 2 * 3 * 3 * x 15 &= 3 * 5 Notice that they only share one factor, 3. This means their greatest common factor (GCF) is 3. Next, rewrite each term as a product involving the GCF. 18x &= 3 * 6x 15 &= 3 * 5 Finally, rewrite the expression by factoring out 3.
18x+15 &= 3* 6x + 3* 5 &= 3(6x+5)
Factor out the indicated whole number from the given expression.
We are asked to factor out 3 from the following expression. 3x+6 We can start by rewriting each term as a product that includes 3 as a factor. 3x &= 3 * x 6 &= 3 * 2 Next, rewrite the expression accordingly. 3x+6 = 3* x + 3 * 2 Finally, we can factor out 3 as requested. 3* x + 3 * 2 = 3 (x+2)
Let's take a look at the next expression.
15y+25
This time we are asked to factor out 5 from the expression. Begin by writing each term as a product that includes 5 as a factor.
15y &= 5 * 3y
25 &= 5 * 5
Use this to rewrite the original expression.
15y+25 = 5* 3y + 5 * 5
Finish by factoring 5 out from the expression.
5* 3y + 5 * 5 = 5(3y+5)
Let's take a look at the last expression.
16z+2
This time we want to factor out 2 from the expression. Rewrite each term as a product involving 2 as a factor.
16z &= 2 * 8z
2 &= 2 * 1
Rewrite the original expression using the factored form of each term.
16z+2 = 2* 8z + 2 * 1
Finish by factoring 2 out of the expression.
2 * 8z + 2 * 1 = 2 (8z+1)
Factor out the indicated integer from each given expression.
We are asked to factor out 7 from the following expression. 14a-7 We will start by rewriting each term as a product that includes 7 as a factor. 14a &= 7 * 2a 7 &= 7 * 1 Next, rewrite the expression accordingly. Keep in mind that the original expression is a subtraction expression. 14a-7 = 7* 2a - 7 * 1 Finally, we can factor out 7, as requested. 7* 2a - 7 * 1 = 7 (2a-1)
Let's take a look at the next expression.
16b-20
This time we are asked to factor out 4 from the expression. Begin by writing each term as a product that includes 4 as a factor.
16b &= 4 * 4b
20 &= 4 * 5
Use this to rewrite the original expression.
16b-20 = 4* 4b - 4 * 5
Finish by factoring 4 out from the expression.
4* 4b - 4 * 5 = 4(4b-5)
Let's take a look at the last expression.
-9 c+6
This time we want to factor out 3 from the expression. Rewrite each term as a product involving 3 as a factor.
-9c &= 3 * (- 3c)
6 &= 3 * 2
Rewrite the original expression using the factored form of each term.
- 9c+6 = 3* (- 3c) + 3 * 2
Finish by factoring 3 out of the expression.
3 * (- 3c) + 3 * 6 = 3 (- 3c+2)
Factor out the indicated rational number from each given expression.
We are asked to factor out 12 from the following expression. 3/2p+5/2 Let's start by rewriting each term as a product that includes 12 as a factor. 3/2p &= 1/2 * 3p [0.8em] 5/2 &= 1/2 * 5 Next, rewrite the expression accordingly. 3/2p+5/2 = 1/2 * 3p + 1/2 * 5 Finally, we can factor out 12, as requested. 3/2p+5/2 = 1/2 (3p+5)
Let's take a look at the next expression.
2q+2/3
This time we are asked to factor out 13 from the expression. However, notice that the term 2q has no 3 in the denominator. Let's try rewriting 2q to make it easier to factor out 13.
Now we can rewrite the original expression so that both terms have 3 in the denominator. 2q+2/3 = 6q/3 + 2/3 We can now rewrite each term as a product that includes 13 as a factor. 6q/3 &= 1/3 * 6q [0.8em] 2/3 &= 1/3 * 2 Use this to rewrite the sum. 6q/3+2/3 = 1/3 * 6q + 1/3 * 2 Finish by factoring 13 out from the expression. 1/3 * 6q + 1/3 * 2 = 1/3(6q+2)
Factor out the greatest common factor from the given expression.
Let's take a look at the given expression. 20x+50 We are asked to factor out the greatest common factor (GCF) of the expression. Let's start by finding the factors of each term. 20x &= 2 * 2 * 5 * x 50 &= 2 * 5 * 5 These terms share the factors 2 and 5, so the GCF is 2 * 5= 10. We can now rewrite each term as a product that involves the GCF. 20x &= 10 * 2x 50 &= 10 * 5 This lets us rewrite the original expression. 20x+50= 10 * 2x + 1 * 5 Finally, we can factor out the GCF. 10 * 2x + 1 * 5 = 10(2x+5)
Let's look at the next expression.
21y+14
We also want to factor out the GCF from the expression. Start by writing the factors of each term.
21y &= 3y * 7
14 &= 2 * 7
This time, the terms only share one common factor, 7. This is the GCF. We can now rewrite the expression like we did in Part A.
21y+14 = 7 * 3y + 7 * 2
We finish by factoring out the GCF.
7 * 3y + 7 * 2 = 7(3y+2)
Determine whether the expression given in each case is a monomial.
Let's take a look at the given expression. 3x^2 The variable is x and the coefficient is 3. The exponent of the variable is 2. 3 x^2 Since the variable is not in a denominator and its exponent is a positive integer, the expression is a monomial.
Let's take a look at the next expression.
5/y^3
The variable is y and the coefficient is 5. The exponent of the variable is 3.
5/y^3
However, the variable is in the denominator of the fraction, so the expression is not a monomial.
Let's take a look at the last expression.
3z/4
Before we identify the coefficient and the variable of this expression, let's rewrite it.
3z/4 = 3/4 * z
We can see that the variable is z and the coefficient is 34. Since there is no exponent written in the variable, it is assumed to be 1.
3/4 z^1
Since the variable is not in the denominator and its exponent is a positive integer, the expression is a monomial.
Determine whether the monomial given in each case is a linear expression.
Let's take a look at the given monomial. 5a^2 We can see that the variable is a and its exponent is 2. 5 a^2 Since the exponent of the variable is not 1, this monomial is not a linear expression.
Let's take a look at the next monomial.
b
This monomial is just the variable b. When no exponent is written on a variable, it is assumed to be 1.
b^1
There is only one variable in this monomial and its exponent is 1, which means that this monomial is a linear expression.
Let's take a look at the last monomial.
1/2c
This time the variable is c. Once again, there is no exponent written on it, so it is assumed to be 1.
1/2 c^1
This monomial also has only one variable and its exponent is 1, so the monomial is a linear expression.