Unit: Expressions and System of Equations
Understanding Expressions and System of Linear Inequalities
Expressions:
- Basics: Expressions are mathematical phrases that combine numbers, variables, and operations (like addition, subtraction, multiplication, and division).
- Types:
- Algebraic: Contains variables and constants.
Example: 3x + 5.
Numeric: Purely numerical, without variables.
Example: 12 – 4.
Types of Expressions:
- Monomial: Single term expression (e.g., 3x, -7).
- Binomial: Two terms expression (e.g., 2x + 5, y – 1).
- Trinomial: Three terms expression (e.g., x2 + 3x – 4, a + b + c).
- Polynomial: Any expression with multiple terms (can include monomial, binomial, trinomial).
- Components:
- Variables: Represented by letters and can take different values.
- Constants: Fixed values.
- Operators: Symbols like +, -, ×, ÷, representing operations.
- Evaluating Expressions:
- Substitute the values of variables and simplify using order of operations (PEMDAS/BODMAS).
- PEMDAS: Parentheses, Exponents, Multiplication and Division (left to right), Addition and Subtraction (left to right)
- BODMAS: Brackets, Orders (exponents), Multiplication and Division (left to right), Addition and Subtraction (left to right)
Systems of Linear Inequalities:
- Definition: A set of linear inequalities involving the same set of variables.
- Linear Inequality: An inequality that can be written in the form ax + by ≤ c or ax + by ≥ c.
- Graphical Representation:
- Each inequality corresponds to a shaded region on the coordinate plane.
- The solution is the overlapping/shaded region common to all inequalities.
- Solution Methods:
- Graphical Method: Plot each inequality on the coordinate plane and find the overlapping region.
- Algebraic Method: Solve each inequality separately and then find the common solution region.
- Types of Solutions:
- Feasible Region: The set of points that satisfy all the given inequalities.
- Bounded Region: When the feasible region is finite.
- Unbounded Region: When the feasible region extends indefinitely.
- Testing Solutions:
- Substitute test points into the original inequalities to check if they satisfy all conditions.
Key Tips for Revision:
- Practice evaluating various types of expressions.
- Understand the graphical representation of linear inequalities.
- Practice solving systems of linear inequalities both graphically and algebraically.
- Test solutions to ensure they satisfy all conditions.