Learn on PengiYoshiwara Intermediate AlgebraChapter 1: Linear Models

Lesson 1: Linear Models

In this Grade 7 lesson from Yoshiwara Intermediate Algebra, students learn how to represent real-world relationships using three mathematical tools: tables of values, graphs, and algebraic equations. The lesson introduces the concept of a linear model through practical examples, such as writing an equation for commission-based income and calculating bike rental costs using expressions like C = 5 + 3t. Students practice moving between all three representations to analyze data, identify trends, and make predictions from a linear relationship.

Section 1

📘 Linear Models

New Concept

A linear model simplifies reality by describing a variable that changes at a constant rate. We'll represent these relationships with tables, graphs, and the equation y=(starting value)+(rate)×ty = \text{(starting value)} + \text{(rate)} \times t.

What’s next

Now, let's put this into practice. You'll work through interactive examples, building linear models using tables, graphs, and equations from word problems.

Section 2

Mathematical model

Property

A mathematical model is a simplified description of reality that uses mathematics to help us understand a system or process. We can represent the relationship between variables by:

  • a table of values
  • a graph
  • an algebraic equation

Examples

For a bike rental with a 5 dollar fee and 3 dollars per hour rate, the cost CC for time tt can be shown as a table: (0, 5), (1, 8), (2, 11).

Section 3

Linear model

Property

A linear model describes a variable that increases or decreases at a constant rate. It has the form

y=(starting value)+(rate)×ty = \text{(starting value)} + \text{(rate)} \times t

Examples

April's income is 200 dollars per week plus 9% commission on sales SS. Her income II is I=200+0.09SI = 200 + 0.09S.

Section 4

Evaluating expressions vs. solving equations

Property

For an equation like C=5+3tC = 5 + 3t:

  • Evaluating an expression means finding the value of CC when a value for tt is given.
  • Solving an equation means finding the value of tt when a value for CC is given.

Examples

To find the cost of a 6-hour bike rental using C=5+3tC = 5 + 3t, you evaluate: C=5+3(6)=23C = 5 + 3(6) = 23 dollars.

Section 5

Decreasing linear models

Property

A decreasing linear model describes a quantity that reduces at a constant rate. The rate is subtracted from the starting value. For a starting value of 20 and a rate of 112\frac{1}{12} per mile dd, the equation is:

g=20−112dg = 20 - \frac{1}{12}d

Examples

Book overview

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Continue this chapter

Chapter 1: Linear Models

  1. Lesson 1Current

    Lesson 1: Linear Models

  2. Lesson 2

    Lesson 2: Graphs and Equations

  3. Lesson 3

    Lesson 3: Intercepts

  4. Lesson 4

    Lesson 4: Slope

  5. Lesson 5

    Lesson 5: Equations of Lines

  6. Lesson 6

    Lesson 6: Chapter Summary and Review

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

📘 Linear Models

New Concept

A linear model simplifies reality by describing a variable that changes at a constant rate. We'll represent these relationships with tables, graphs, and the equation y=(starting value)+(rate)×ty = \text{(starting value)} + \text{(rate)} \times t.

What’s next

Now, let's put this into practice. You'll work through interactive examples, building linear models using tables, graphs, and equations from word problems.

Section 2

Mathematical model

Property

A mathematical model is a simplified description of reality that uses mathematics to help us understand a system or process. We can represent the relationship between variables by:

  • a table of values
  • a graph
  • an algebraic equation

Examples

For a bike rental with a 5 dollar fee and 3 dollars per hour rate, the cost CC for time tt can be shown as a table: (0, 5), (1, 8), (2, 11).

Section 3

Linear model

Property

A linear model describes a variable that increases or decreases at a constant rate. It has the form

y=(starting value)+(rate)×ty = \text{(starting value)} + \text{(rate)} \times t

Examples

April's income is 200 dollars per week plus 9% commission on sales SS. Her income II is I=200+0.09SI = 200 + 0.09S.

Section 4

Evaluating expressions vs. solving equations

Property

For an equation like C=5+3tC = 5 + 3t:

  • Evaluating an expression means finding the value of CC when a value for tt is given.
  • Solving an equation means finding the value of tt when a value for CC is given.

Examples

To find the cost of a 6-hour bike rental using C=5+3tC = 5 + 3t, you evaluate: C=5+3(6)=23C = 5 + 3(6) = 23 dollars.

Section 5

Decreasing linear models

Property

A decreasing linear model describes a quantity that reduces at a constant rate. The rate is subtracted from the starting value. For a starting value of 20 and a rate of 112\frac{1}{12} per mile dd, the equation is:

g=20−112dg = 20 - \frac{1}{12}d

Examples

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 1: Linear Models

  1. Lesson 1Current

    Lesson 1: Linear Models

  2. Lesson 2

    Lesson 2: Graphs and Equations

  3. Lesson 3

    Lesson 3: Intercepts

  4. Lesson 4

    Lesson 4: Slope

  5. Lesson 5

    Lesson 5: Equations of Lines

  6. Lesson 6

    Lesson 6: Chapter Summary and Review