BackComprehensive Study Guide: College Algebra Essentials
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Algebraic Expressions and Simplification
Simplifying Rational and Radical Expressions
Algebraic expressions often require simplification by applying exponent rules, combining like terms, and rationalizing denominators.
Exponent Rules: When multiplying or dividing like bases, add or subtract exponents respectively.
Radical Simplification: Simplify radicals by factoring out perfect squares and rationalizing denominators.
Example:
Simplify
Apply exponent rules and simplify each variable separately.
Combining Like Terms and Distributive Property
Expressions can be simplified by combining like terms and using the distributive property to expand or factor expressions.
Like Terms: Terms with the same variable and exponent can be combined.
Distributive Property:
Example: simplifies to
Polynomial Operations
Multiplying and Factoring Polynomials
Polynomials can be multiplied using the distributive property or special products, and factored by grouping or using formulas.
Multiplying Binomials: Use FOIL (First, Outer, Inner, Last) for .
Factoring Quadratics: Find two numbers that multiply to and add to in .
Example: Factor as
Solving Equations
Linear, Quadratic, and Radical Equations
Equations can be solved by isolating the variable, factoring, or applying the quadratic formula. Always check for extraneous solutions, especially with radicals.
Quadratic Formula:
Square Root Method: If , then
Example: Solve yields
Absolute Value Equations
Absolute value equations have two possible solutions, one for the positive and one for the negative case.
General Form: implies or
Example: gives or
Functions and Graphs
Identifying Functions and Their Properties
A function assigns exactly one output to each input. The vertical line test can determine if a graph represents a function.
Vertex of a Parabola: For , the vertex is
Example: has vertex
Evaluating and Composing Functions
To evaluate a function, substitute the input value into the function's formula. Composition involves plugging one function into another.
Example: If , then
Transformations of Functions
Transformations include translations, reflections, stretches, and compressions.
Vertical Shift: shifts up by units.
Horizontal Shift: shifts right by units.
Reflection: reflects over the x-axis.
Linear Functions and Applications
Writing Equations of Lines
The slope-intercept form of a line is , where is the slope and is the y-intercept.
Parallel Lines: Have the same slope.
Perpendicular Lines: Slopes are negative reciprocals.
Example: Line through parallel to is
Linear Models and Applications
Linear functions can model real-world situations, such as depreciation of assets.
General Linear Model:
Example: A mower purchased for depreciates by $800V(t) = -800t + 12,000$
Operations with Functions
Function Arithmetic
Functions can be added, subtracted, multiplied, or divided, provided the domain allows.
Example: If and , then
Inequalities and Absolute Value
Solving Inequalities
Inequalities are solved similarly to equations, but the direction of the inequality reverses when multiplying or dividing by a negative number.
Example:
Factor:
Solution: or
Summary Table: Key Algebraic Concepts
Concept | Key Formula/Property | Example |
|---|---|---|
Quadratic Formula | ||
Slope-Intercept Form | ||
Vertex of Parabola | in | for |
Absolute Value Equation | or | or |
Additional info:
Some context and explanations have been expanded for clarity and completeness.
Graphical questions (e.g., determining if a graph is a function) rely on the vertical line test.
Transformation descriptions are based on standard function transformation rules.