Grade 9 Revision Session

Introduction

• Welcome note by Confident
• Targeted for Grade 9 students preparing for Term 2
• Topics covered:
  • Algebraic expressions
  • Algebraic equations
  • Functions and relationships
• Subscription reminder to receive future lessons

Algebraic Expressions

Understanding the Basics

• Components of an Algebraic Expression:
  • Variable: Represented by letters (e.g., x)
  • Coefficient: Number before the variable (e.g., in 3x, 3 is the coefficient)
  • Constant Term: Number without variable (e.g., +2)

Example

• Expression: 3x^2 - 4x + 2
  • Variable is x
  • Coefficient of x^2 is 3
  • Coefficient of x is -4
  • Constant term is 2

Recap Example

• Expression: -4a^3 + 5
  • Variable is a
  • Coefficient of a^3 is -4
  • Constant term is 5

Algebraic Terms

Identifying Parts

• Expression Example: 2x^2 - 18xy - 7
  • Terms: 4 terms in the expression
  • Constant term: -7
  • Coefficient of x^2: 2
  • Coefficient of y^2: -9
  • Coefficient of x in -18xy: -18y
  • Coefficient of y in -18xy: -18x

Substitution

• Given values: x = 2, y = -3
• Substituting into 2x^2 - 18xy - 7
  • Calculate using substitution to get:
  • Result: 109

Like and Unlike Terms

Definitions

• Like Terms: Same variables and powers
  • Example: 2x and 5x are like terms
• Unlike Terms: Different variables or powers
  • Example: 3x^2 and 3x are unlike terms

Examples

• 3xy and 5yx are like terms
• 2x^2y and 6xy^2 are unlike terms due to different power distribution

Addition and Subtraction

Basic Arithmetic with Terms

• Like terms can be added or subtracted
  • Example: 3x + 2x = 5x
  • Avoid: 3x + 2x ≠ 5x^2
• Unlike terms cannot be simplified further
  • Example: 3x + 5y remains 3x + 5y

Handling Negative Signs

• Example: 2x - 3x + 5y - 8y
  • Calculate separately: 2 - 3 = -1 for x terms
  • Calculate separately: 5 - 8 = -3 for y terms
  • Result: -1x - 3y

Conclusion

• Next lesson focus:
  • Division and multiplication of terms
• Encouragement to subscribe for updates
• Aimed to build a strong foundation for exams

Final Note

• Emphasis on practice and understanding
• Stay tuned for next lessons on advanced topics
• Motivation for achieving high scores and parental pride
• Reminder to subscribe for easy access to future content