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Review of Variables

Site: Saylor Academy
Course: GKT101: General Knowledge for Teachers – Math
Book: Review of Variables
Printed by: Guest user
Date: Monday, May 20, 2024, 2:14 AM

Description

While arithmetic deals primarily with operations with numbers, in algebra, you will deal with expressions that involve variables–letters that represent real numbers. Watch this lecture series to review the concept of a variable and the conventional way to write basic expressions involving variables. Complete the interactive exercises.

Table of contents

Why aren't we using the multiplication sign?

Evaluating an expression with one variable

Evaluating expressions with one variable - Questions

1. Evaluate \frac{n}{6} + 2 when n = 12 .

2. Evaluate 6 + x when x = 3.

3. Evaluate \frac{15}{k} when k = 3 .

4. Evaluate 4g - 12 when g = 5.

5. Evaluate \frac{j}{4} when j = 12 .

6. Evaluate c - 2 when c = 7.

7. Evaluate 9 - \frac{8}{S} when S = 4.

Answers

1. Let's substitute 12 for n.

\frac{n}{6} + 2

= \frac{12}{6} + 2

= 2 + 2

= 4


2. Let's substitute 3 for x.

6 + x

= 6 + 3

= 9


3. Let's substitute 3 for k.

\frac{15}{k}

= \frac{15}{3}

= 5


4. Let's substitute 5 for g.

4g - 12

= 4(5) - 12

= 20 - 12

= 8


5. Let's substitute 12 for j.

\frac{j}{4}

= \frac{12}{4}

= 3


6. Let's substitute 7 for c.

c - 2

= 7 - 2

= 5


7. Let's substitute 4 for S.

9 - \frac{8}{S}

= 9 - \frac{8}{4}

= 9 - 2

= 7