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Basic Algibra in Computational Mathematics
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1. Basic Concepts of Algebra By : H. F. K. M. Fonseka M.Sc. in IT (in Reading) , UOM B.Sc. (Special in Computer Science), SEUSL 5/28/2025 1
Content 1. Introduction to Algebraic Expressions 2. Basic Operations with Algebraic Expressions 3. Laws of Exponents 4. Solving Linear Equations 5/28/2025 2
Algebraic Expressions • An algebraic expression is a mathematical phrase that includes numbers, variables, and operations. Ex : ?? + ? • Components: • Numbers (constants) • Variables (Ex: x, y) • Operations (+, -, ×, ÷) 5/28/2025 3
Introduction to Terms, Coefficients, Variables, and Constants • Term: A part of an expression separated by + , –, * or / Ex: 3x + 5 • Coefficient: The numerical part of a term with a variable Ex: 3 in 3x • Variable: A symbol representing an unknown value Ex: x • Constant: A fixed number without variables Ex: 5 5/28/2025 4
Practice Problems Considering the given equations, identify the terms. 1. 5? + 3? 2. 7? − 3 3. 6? + 8 4. 2?2+ 2 5. 3?3+ 2?2+ 3? + 3 5/28/2025 5
Simplifying Expressions • The Combining terms must have the same variables raised to the same powers. • Combine them under mathematical operations. • Example: • 4? + 3? = ?? • 2? + 5 − 3? + 1 = −? + ? 5/28/2025 6
Practice Problems Simplify ➔ 1. 5? + 2? – 3 2. 2? + 4? − ? + 6? 3. (3? + 4) + (2? − 5) 4. 7? − 3 = 5? 5. 6? + 8 = 5 5/28/2025 7
Basic Operations • Four basic operations on algebraic expressions: - Addition - Subtraction - Multiplication - Division - These operations follow algebraic rules and involve combining like terms, applying distributive law, and simplifying. 5/28/2025 8
Addition and Subtraction of Algebraic Terms • Combine the terms: • 3x + 5x = 8x • 4a - 2a = 2a Example: (2? + 3) + (4? − 5) = 6? − 2 • Always group the terms before simplify. 5/28/2025 9
Multiplication and Division of Algebraic Terms Multiply and divide the coefficients, when applicable. • ? × ? = ?? • 2? × 3? = 6?? • 6?? ÷ 3? = 2? • (2?)(3?) = 6?? • (4?²?) ÷ (2?) = 2?? 5/28/2025 10
Distributive Property • The distributive property allows multiplying a single term by terms inside parentheses: • a(b + c) = ab + ac • Example: 3(x + 2) = 3x + 6 • Use it to simplify expressions before combining the terms. 5/28/2025 11
Introduction to Exponents • Exponents represent repeated multiplication. Example: ?³ = ? × ? × ? • Base → : The number being multiplied • Exponent → : How many times the base is multiplied by itself • Example: 2⁴ = 2 × 2 × 2 × 2 = 16 Exponent 24 Base 5/28/2025 12
Laws of Exponents 1. Product Rule: ?ᵐ × ?ⁿ = ?ᵐ⁺ⁿ 2. Quotient Rule: ?ᵐ ?ⁿ= ?ᵐ⁻ⁿ,? ≠ 0 3. Power Rule: ?ᵐ ⁿ = ??∗? Examples: • 3² × 3⁴ = 3⁶ 56 52= 5⁴ • (2³)² = 2⁶ • 5/28/2025 13
Zero & Negative Powers • Zero Exponent: ?⁰ = 1 (??? ? ≠ 0) • Negative Exponent: ?⁻ⁿ = 1 / ?ⁿ • Examples: • 4⁰ = 1 • 2⁻³ = 1 / 8 5/28/2025 14
Simplify: ?3?−2 2 ? ?−1 • Steps: 1. Expand the numerator: ?⁶ ?⁻⁴ 2. Divide: ?6 ? ?−4 ?−1= ?⁻³ = ?⁵ 3. Final Answer: ?5 ?3 5/28/2025 15
Practice Problems ?3⋅?−22 ?.?−1 • (3²)³ = ? • a⁵ / a² = ? • x⁰ = ? • 2⁻² = ? = ? • 3 ?2⋅?−3 (?4⋅?−2)= ? • 2 ?−1⋅?2 (?−3⋅?) ?4⋅?−13 ?2⋅?2 ?−2⋅?32 ?−1⋅?−4= ? = ? • = ? • • 5/28/2025 16
Linear Equations • A linear equation is an equation that makes a straight line when graphed. y • Standard form: ?? + ? = ? ? = ? • The variable (usually x) has an exponent of 1. 0 x ??= ? 5/28/2025 17
Solving One-Variable Equations: Step by Step Steps: 1. Rearrange the variables and all constants for the both sides. 2. Simplify both sides (if needed). 3. Use inverse operations to isolate the variable. 4. Solve for the variable. Example: • 2? + 3 = 11 subtract 3 from both sides, 2? + 3 − 3 = 11 – 3 2? = 8 divide both sides by 2, 2? 2=8 ? = ? 2 5/28/2025 18
Inverse Operations • Inverse operations undo each other: • Addition ↔ Subtraction • Multiplication ↔ Division • Used to isolate the variable in an equation. Example: • ? + 5 = 9 → ? = 9 − 5 = 4 • 3? = 12 → ? = 12 ÷ 3 = 4 5/28/2025 19
Practice Problems Find the value of the variable that makes the equation true. 1. 7? + 8 = 5? 2. 3? + 5 = 2? + 1 3. 4 + 8? = 3 – 8? 4. 10? + 7 = 5? 5/28/2025 20
???????????? • After solving, substitute the value back into the original equation. • If both sides are equal, the solution is correct. Example: • Equation: 2? + 3 = 11 • Solution: ? = 4 • Check: 2(4) + 3 = 8 + 3 = 11 ✓ 5/28/2025 21
Practice Problems Check your answers by substitution! 1. x + 7 = 10 → x = ? 2. 5x = 20 → x = ? 3. 3x - 4 = 8 → x = ? 4. 4 + 8? = 3 – 8? → x = ? 5. 10? + 7 = 5? → x = ? 5/28/2025 ICBT , International Diploma in IT 22
Summary • Linear equations have one variable. • Use inverse operations to isolate the variable. • Always check your solution by substitution. 5/28/2025 23
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