Study Notes
Substitution in algebra involves replacing variables with given values and performing calculations according to the order of operations.
- Substitution — replacing the value of an unknown with the given value. Example: Find the value of 3m – 5 when m = 6. 3m – 5 = 3 x 6 – 5 = 18 – 5 = 13
- Order of Operations — the sequence in which operations are performed in a mathematical expression. Example: Evaluate 3x + 4y when x = 10 and y = 2. 3 x 10 + 4 x 2 = 30 + 8 = 38
Exam Tips
Key Definitions to Remember
- Substitution: replacing variables with given values
- Order of Operations: the sequence of operations in calculations
Common Confusions
- Forgetting to follow the order of operations
- Incorrectly substituting values into expressions
Typical Exam Questions
- What is the value of 3m – 5 when m = 6? 13
- Evaluate 3x + 4y when x = 10 and y = 2? 38
- Evaluate 2x^2 + 3x + 8 when x = 4? 52
What Examiners Usually Test
- Correct substitution of values into expressions
- Accurate computation following the order of operations