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Graphs of linear equations and functions

Lisa Chen

Lisa Chen

7 min read

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Study Guide Overview

This study guide covers linear equations and graphs, focusing on key concepts like slope, y-intercept, and different equation forms (slope-intercept, point-slope, and standard). It also explores graphing techniques, parallel/perpendicular lines, and real-world applications, including modeling and problem-solving. Finally, it provides practice questions and exam tips for the AP SAT (Digital).

Linear Equations and Graphs: Your Ultimate Study Guide 🚀

Hey there! Let's get you prepped for the AP SAT (Digital) with a super focused review of linear equations and graphs. This is a BIG topic, so let’s make sure you’re totally comfortable with it. Think of this as your go-to resource for acing those questions!

Understanding the Basics

Linear equations and functions are all about straight lines. They show how two variables relate, and mastering them is crucial for the exam. Let's break it down:

Key Concept

Slope and Y-intercept: The Dynamic Duo

  • Slope (m): The rate of change. How much does 'y' change for every change in 'x'?

    • Rise over run: Vertical change / Horizontal change. Think of it as climbing a hill (or going down one!).
    • Positive slope: Line goes up from left to right. ↗️
    • Negative slope: Line goes down from left to right. ↘️
    • Zero slope: Horizontal line. ↔️
    • Undefined slope: Vertical line. ↕️
  • Y-intercept (b): Where the line crosses the y-axis. It's the 'y' value when 'x' is zero. Often your starting point or initial value.

Memory Aid

Remember: Slope is the steepness of the line and the y-intercept is where the line begins on the y-axis.


Equations of Lines: Your Toolkit

Key Concept

Slope-Intercept Form

  • Equation: y=mx+by = mx + b
    • m is the slope.
    • b is the y-intercept.
    • Super useful when you know the slope and y-intercept directly from the graph.

Point-Slope Form

  • Equation: yy1=m(xx1)y - y₁ = m(x - x₁)
    • (x₁, y₁) is a point on the line.
    • m is the slope.
    • Great when you have a point and...

Question 1 of 12

What is the y-intercept of the line represented by the equation y=3x5y = 3x - 5?

3

-5

5

0