
Writing
Algebraic Equations 

Unit 7
> Lesson 5 of 8 
Problem: 
Jeanne has $17 in her piggy bank. How much money does she need to buy a game that costs $68?


Solution: 
Let x represent the amount of money Jeanne needs. Then the following equation can represent this
problem: 

17 + x = 68 

We can subtract 17 from both sides of the equation to find the value of x. 

68  17 = x 
Answer: 
x = 51, so Jeanne needs $51 to buy the game. 
In the problem above, x is a
variable.
The symbols 17 + x = 68 form an
algebraic equation.
Let's look at some examples of writing algebraic equations.
Example 1:

Write each sentence as an algebraic equation.



Sentence 
Algebraic Equation 
A number increased by nine is fifteen. 
y + 9 = 15 
Twice a number is eighteen. 
2n = 18 
Four less than a number is twenty. 
x  4 = 20 
A number divided by six is eight. 


Example 2:

Write each sentence as an algebraic equation.



Sentence 
Algebraic Equation 
Twice a number, decreased by twentynine, is seven. 
2t  29 = 7 
Thirtytwo is twice a number increased by eight. 
32 = 2a + 8 
The quotient of fifty and five more than a number is ten. 

Twelve is sixteen less than four times a number. 
12 = 4x  16 

Example 3:

Write each sentence as an algebraic equation.



Sentence 
Algebraic Equation 
Eleni is x years old. In thirteen years she will be twentyfour years old. 
x + 13 = 24 
Each piece of candy costs 25 cents. The price of h pieces of candy is $2.00. 
25h = 200 or 
.25h = 2.00 
Suzanne made a withdrawal of d dollars from her savings account. Her old balance
was $350, and her new balance is $280. 
350  d = 280 
A large pizza pie with 15 slices is shared among p
students so that each student's share is 3 slices. 


Summary: 
An algebraic equation is an equation that includes one or more variables. In this lesson,
we learned how to write a sentence as an algebraic equation.

Exercises
Directions: Select the algebraic equation that correctly represents the given sentence. Select your answer by clicking on its button. Feedback to your answer
is provided in the RESULTS BOX. If you make a mistake, choose a different button. 
1. 
Twice a number is twentyeight. 



2. 
The quotient of thirtynine and a number is three. 



3. 
Five less than three times a number is fortysix. 



4. 
Three is twentyone, divided by the sum of a number and five. 



5. 
Eric had $197 in his savings account before he was paid his weekly salary. His
current savings balance is $429. How much money does Eric earn each week? 



This interactive lesson is by Gisele Glosser. You can find me on Google.
