Functions and Equations Review Summary

Dec 5, 2024

EOC Review Lecture Notes

Function Identification from Tables

  • Table 1: X values increase by 1, f(x) values increase by 3.
    • Conclusion: Linear function due to constant first differences.
  • Table 2: X values increase by 1, f(x) values increase by multiplying by 4.
    • Conclusion: Exponential function due to repeated multiplication (times 4).

Evaluating Functions

  • Example: Evaluate f(-3) for a given quadratic function.
    • Substitute x = -3 into f(x).
    • Calculation: f(-3) = -18 + 9 + 1 = -8.

Key Features of Quadratic Functions

  • Vertex: The highest or lowest point (e.g., (-1, 4)).
  • Axis of Symmetry: x = -1 (from vertex x-coordinate).
  • Domain and Range:
    • Domain: All real numbers.
    • Range: y ≤ 4 (maximum value).
  • End Behavior: As x → ±∞, y → -∞ (both ends of the parabola point down).
  • Increasing/Decreasing Intervals:
    • Increasing: x < -1.
    • Decreasing: x > -1.

Solving Systems of Equations

  • Method Used: Elimination.
    • Example: Eliminate variables by multiplying and adding equations.
  • Example Solution: x = 2, y = 2.

Simplifying Expressions with Exponents

  • Negative Exponents: Move terms between numerator and denominator to make exponents positive.
    • Example: Simplify to x * y^5 / 3 after adjustments.

Solving Radical Expressions

  • Cube Roots: Identify perfect cubes (like 8, 27) for simplification.
  • Simplifying: Combine terms under a single radical (e.g., 16 * cube root of 20).

Graphing Linear Equations

  • Slope-Intercept Form: y = mx + b.
    • Example: Slope = 3/4, y-intercept = -2.
    • Plot points using rise over run.

Comparing Linear Functions

  • Slope Comparison: Determine greater slope between functions.
  • Intercepts:
    • Y-Intercept: Found by setting x = 0.
    • X-Intercept: Found by setting y = 0 (solve for x).

Writing Inequalities from Graphs

  • Identifying Inequality: Based on line shading (above = ">", dashed line = no "=").
  • Example: y > -x - 2.

Solving Absolute Value Equations

  • Steps: Isolate absolute value, solve two resulting equations.
  • Example Solutions: x = 0 or x = -1.

Calculating Simple Interest

  • Formula: A = P(1 + rt).
  • Example: Calculate total after 10 years for given P and r.

Solving Word Problems with Systems

  • Scenario: Solve cost of shirts and pants using elimination.
  • Solution: x = $16.66 (shirts), y = $16.67 (pants).

Writing Equation of a Parabola

  • Vertex Form: y = a(x - h)^2 + k.
  • Convert to Standard Form: Expand and combine like terms.
  • Verification: Plug in points to verify equation accuracy.

Maximizing Profit in Quadratics

  • Vertex Calculation: Use -b/(2a) for maximum price calculation.
  • Example: Maximize profit with $3.50 ticket price.

Writing Perpendicular Line Equations

  • Identify Perpendicular Slope: Negative reciprocal of given slope.
  • Point-Slope Form: Convert to slope-intercept form.

Describing End Behavior of Functions

  • Exponential Function: End behavior as x approaches ±∞.
  • Y-Value Behavior: Describe increase/decrease towards zero.