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Housekeeping Did you complete the Unit 1 summative assessment?

Writing equations using symbols

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Housekeeping

Did you complete the Unit 1 summative assessment?

In this unit, you will solve single and multi-step linear equations. You will recognize and give examples of linear equations that have none, one, or infinitely many solutions.

Unit 2 Overview

Linear EquationNon-Linear EquationSolutionIdentityTermsLike TermsEquivalent ExpressionSimplifyDistributionProperties of EqualityInverse OperationsCoefficientVariable

Unit 2 Vocabulary

Unit 2 Level of Understanding- Level 2

Comprehend Vocabulary Identify the number of solutions of a given

equation Give an example of an equation with a given

number of solutions

Solve a Linear Equation Single and Multi-Step Using Distribution Collecting Like Terms Identify the number of solutions

Unit 2 Level of Understanding- Level 2

Unit 2: Lesson 1

Writing Equations Using Symbols

Compare the following:

The number 1,157 is the sum of the squares of two consecutive odd integers divided by the difference between the two consecutive odd integers.

How are they related?

Discussion Time

Using letters to represent numbers in mathematical statements was introduced by René Descartes in the 1600s. In that era, people used only words to describe mathematical statements. Use of letters, or symbols, to represent numbers not only brought clarity to mathematical statements, it also expanded the horizons of mathematics.

History of Math

The reason we want to learn how to write a mathematical statement using symbols is to save time and labor.

Imagine having to write the sentence: “The number 1,157 is the sum of the squares of two consecutive odd integers divided by the difference between the two consecutive odd integers.”

Then, imagine having to write the subsequent sentences necessary to solve it; compare that to the following:

Let x represent the first odd integer. Then,

1,157=𝑥2+(𝑥+2)2

(𝑥−2 )−𝑥

All of the mathematical statements in this lesson are equations. Recall that an equation is a statement of equality between two expressions. Developing equations from written statements forms an important basis for problem solving and is one of the most vital parts of algebra.

Throughout this unit, there will be work with written statements and symbolic language. You will work first with simple expressions, then with equations that gradually increase in complexity, and in Unit 3 you will work with systems of equations (more than one equation at a time).

Example 1: We want to express the following statement using symbolic language:

A whole number has the property that when the square of half the number is subtracted from five times the number, we get the number itself.

Example 2: We want to express the following statement using symbolic language:

A whole number has the property that when half the number is added to 15, we get the number itself.

Example 3: We want to express the following statement using symbolic language:

Paulo has a certain amount of money. If he spends $6.00, then he has of the original amount left.

What is the first thing that must be done before we express this situation using symbols?

Example 4: We want to express the following statement using symbolic language:

When a number is taken away from 57, what remains is four more than 5 times the number.

Example 5: We want to express the following statement using symbolic language:

The sum of three consecutive integers is 372.

Example 6: We want to express the following statement using symbolic language:

The sum of three consecutive odd integers is 93.

Now you try!Write each of the following statements using symbolic language.

1. The sum of four consecutive even integers is -28.2. A number is four times larger than the square of half the

number.3. Steven has some money. If he spends $9.00, then he will

have of the amount he started with.4. The sum of a number squared and three less than twice the

number is 129.5. Miriam read a book with an unknown number of pages. The

first week, she read five less than of the pages. The second week, she read 171 more pages and finished the book. Write an equation that represents the total of pages in the book.

Wrap Up Unit 2 Introduction We know how to write mathematical statements using

symbolic language. Written mathematical statements can be represented

as more than one correct symbolic statement. We must always begin writing a symbolic statement by

defining our symbols (variables). Complicated statements should be broken into parts or

attempted with simple numbers to make the representation in symbolic notation easier.

What Now?Look up vocabulary termsIXL Practice – S.1, S.2, S.3