IndietroCollege Algebra: Review and Foundations Study Notes
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Review of Fundamental Algebraic Concepts
Scientific Notation
Scientific notation is a method of expressing very large or very small numbers in the form a × 10n, where 1 ≤ |a| < 10 and n is an integer.
Purpose: Simplifies calculations and representation of numbers in science and engineering.
Conversion to Scientific Notation: Move the decimal point so that only one nonzero digit remains to the left of the decimal. Count the number of places moved to determine the exponent.
Example: 45,000 = ; 0.00032 =
Addition, Subtraction, and Multiplication of Polynomials
Polynomials are algebraic expressions consisting of variables and coefficients, combined using addition, subtraction, and multiplication.
Addition/Subtraction: Combine like terms (terms with the same variable and exponent).
Multiplication: Use the distributive property or special products (e.g., ).
Example:
Example:
Factoring Polynomials
Factoring is the process of writing a polynomial as a product of its factors.
Common Methods: Factoring out the greatest common factor (GCF), factoring trinomials, difference of squares, and grouping.
Example: (difference of squares)
Example: (factoring out GCF)
Multiplication and Division of Rational Expressions
Rational expressions are fractions where the numerator and denominator are polynomials.
Multiplication: Multiply numerators together and denominators together, then simplify.
Division: Multiply by the reciprocal of the divisor.
Example:
Example:
Addition and Subtraction of Rational Expressions
To add or subtract rational expressions, first find a common denominator.
Steps:
Factor denominators if possible.
Find the least common denominator (LCD).
Rewrite each expression with the LCD.
Add or subtract numerators, keep the denominator.
Simplify if possible.
Example:
Equations and Inequalities
Solving Linear Equations
Linear equations are equations of the first degree (the highest exponent of the variable is 1).
General Form:
Solution:
Example:
Solving Quadratic Equations by Factoring
Quadratic equations are equations of the form .
Factoring: Write the quadratic as a product of two binomials and set each factor to zero.
Example:
Using the Quadratic Formula
The quadratic formula provides solutions to any quadratic equation.
Formula:
Example: or
Addition, Subtraction, and Multiplication of Complex Numbers
Complex numbers are numbers of the form a + bi, where i is the imaginary unit ().
Add/Subtract: Combine real parts and imaginary parts separately.
Multiply: Use distributive property and .
Example:
Example:
Solving an Equation by Factoring
Factoring can be used to solve equations by setting each factor equal to zero.
Example:
Solving Inequalities
Inequalities involve expressions related by <, ≤, >, or ≥.
Linear Inequality: Solve as you would an equation, but reverse the inequality sign when multiplying or dividing by a negative number.
Example:
Graphs and Equations of Lines
Finding the Equation of a Line (Point-Slope Form)
The point-slope form is useful for finding the equation of a line when you know a point and the slope.
Formula: , where is a point on the line and is the slope.
Example: Find the equation of a line through (2, 3) with slope 4:
Finding the Equation of Parallel and Perpendicular Lines
Parallel lines have the same slope; perpendicular lines have slopes that are negative reciprocals.
Parallel: If a line has slope , any parallel line has slope $m$.
Perpendicular: If a line has slope , any perpendicular line has slope (provided ).
Example: Given , a parallel line through (0, 3):
Example: A perpendicular line through (1, -2): Slope is , so