WAEC WAEC Nigeria General Mathematics

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(Algebraic Expressions)

Evaluating Basic Algebraic Expressions

Evaluating Basic Algebraic Expressions

What Are Algebraic Expressions?

An algebraic expression is a mathematical phrase that can include numbers, variables (like x or y), and operation symbols. For example, 3x + 2 is an algebraic expression.

In WAEC exams, you may be asked to evaluate these expressions by substituting given values for the variables.

How to Evaluate Algebraic Expressions

To evaluate an algebraic expression, follow these steps:

  • Substitute: Replace the variables with the given numbers.
  • Calculate: Perform the arithmetic operations.

Examples

Example 1: Evaluate 3x + 2y when x = 60 and y = 20

Worked Example

Given: 3x + 2y

Example 2: Evaluate a^2 - 4b when a = 5 and b = 3

Worked Example

Given: a^2 - 4b

Tuity Tip

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Check Your Work: Always double-check your calculations to avoid simple arithmetic errors.

Use Parentheses: When substituting, use parentheses to avoid mistakes with negative numbers or operations.

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