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  1. AP Digital Sat
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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 πŸš€

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:

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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. β†˜οΈ
    • 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

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Key Concept

Slope-Intercept Form

  • Equation: y=mx+by = 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: yβˆ’y1=m(xβˆ’x1)y - y₁ = m(x - x₁)yβˆ’y1​=m(xβˆ’x1​)
    • (x₁, y₁) is a point on the line.
    • m is the slope.
    • Great when you have a point and...
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Question 1 of 12

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

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-5

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0