Math for Grade 8
1 Number Systems
1-1 Understanding Integers
1-2 Operations with Integers
1-3 Rational Numbers
1-4 Operations with Rational Numbers
1-5 Real Numbers and Their Properties
2 Algebra
2-1 Solving Linear Equations
2-2 Graphing Linear Equations
2-3 Systems of Linear Equations
2-4 Inequalities and Their Graphs
2-5 Polynomials and Their Operations
3 Geometry
3-1 Basic Geometric Figures
3-2 Angles and Their Measurement
3-3 Triangles and Their Properties
3-4 Quadrilaterals and Their Properties
3-5 Circles and Their Properties
3-6 Area and Perimeter of 2D Shapes
3-7 Volume and Surface Area of 3D Shapes
4 Data Handling
4-1 Collecting and Organizing Data
4-2 Measures of Central Tendency
4-3 Graphical Representation of Data
4-4 Probability and Its Applications
5 Functions and Relations
5-1 Introduction to Functions
5-2 Linear Functions and Their Graphs
5-3 Non-Linear Functions and Their Graphs
5-4 Relations and Their Representations
6 Problem Solving and Reasoning
6-1 Mathematical Reasoning
6-2 Problem-Solving Strategies
6-3 Applications of Mathematics in Real-Life Situations
Solving Linear Equations

Solving Linear Equations

Key Concepts

Linear equations are algebraic expressions where the highest power of the variable is 1. Solving linear equations involves finding the value of the variable that makes the equation true. The key concepts include:

1. Understanding Linear Equations

A linear equation is an equation of the form \( ax + b = c \), where \( a \), \( b \), and \( c \) are constants, and \( x \) is the variable. The goal is to isolate \( x \) to find its value.

2. Isolating the Variable

To solve a linear equation, you need to isolate the variable \( x \). This involves performing inverse operations to both sides of the equation to maintain equality.

3. Inverse Operations

Inverse operations are used to cancel out terms. For example, addition and subtraction are inverse operations, as are multiplication and division.

4. Balancing the Equation

Every operation performed on one side of the equation must be performed on the other side to keep the equation balanced.

Detailed Explanation

1. Understanding Linear Equations

Consider the equation \( 2x + 3 = 7 \). Here, \( 2x \) is the term with the variable, \( 3 \) is a constant term, and \( 7 \) is the result of the equation.

2. Isolating the Variable

To isolate \( x \), first, subtract the constant term from both sides of the equation:

\( 2x + 3 - 3 = 7 - 3 \)

\( 2x = 4 \)

3. Inverse Operations

Next, use the inverse operation of multiplication, which is division, to isolate \( x \):

\( \frac{2x}{2} = \frac{4}{2} \)

\( x = 2 \)

4. Balancing the Equation

Throughout the process, each operation is applied to both sides of the equation to maintain balance. This ensures that the equation remains true.

Examples and Analogies

Example 1: Simple Linear Equation

Solve the equation \( 3x - 5 = 10 \).

Step 1: Add 5 to both sides:

\( 3x - 5 + 5 = 10 + 5 \)

\( 3x = 15 \)

Step 2: Divide both sides by 3:

\( \frac{3x}{3} = \frac{15}{3} \)

\( x = 5 \)

Example 2: Using Analogies

Think of solving a linear equation like balancing a seesaw. If you add weight to one side, you must add the same weight to the other side to keep it balanced. Similarly, in an equation, if you add or subtract a number from one side, you must do the same to the other side.

Conclusion

Solving linear equations is a fundamental skill in algebra. By understanding the key concepts of isolating the variable, using inverse operations, and balancing the equation, you can solve any linear equation. Practice with various examples to reinforce your understanding and build confidence in solving linear equations.