Basic Algebra – One Page Guide
1. What is Algebra?
Algebra is a branch of mathematics that uses letters (called variables) to represent unknown numbers. It allows us
to describe patterns, relationships, and solve problems where some values are not known.
2. Variables and Constants
A variable is a letter that stands for an unknown value (e.g. x, y).
A constant is a fixed number (e.g. 3, −7, 10).
Example: In 2x + 5, x is the variable and 2 and 5 are constants.
3. Algebraic Expressions
An algebraic expression is a combination of numbers, variables, and operations (+, −, ×, ÷).
Examples: 3x, 4y − 2, 5a + 7
4. Equations
An equation states that two expressions are equal and always includes an equals sign (=).
Example: 2x + 3 = 11
5. Solving Simple Equations
To solve an equation, find the value of the variable that makes the equation true.
Example:
2x + 3 = 11
Subtract 3 from both sides: 2x = 8
Divide both sides by 2: x = 4
6. Key Rules to Remember
• What you do to one side of an equation, you must do to the other side.
• Combine like terms (e.g. 2x + 3x = 5x).
• Keep equations balanced at all times.