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Linear relationship word problems

Jessica White

Jessica White

6 min read

Study Guide Overview

This guide covers linear relationships for the AP SAT (Digital) exam, focusing on slope (rate of change), y-intercept (starting point), and modeling with linear equations (y = mx + b). It explains how to set up equations from points, slopes, and verbal descriptions, and how to solve and interpret them in real-world contexts. The guide also emphasizes identifying variables, analyzing relationships, and provides practice questions with a scoring breakdown.

Linear Relationships: Your Guide to Conquering Word Problems πŸš€

Hey there! Ready to make word problems your playground? This guide is your go-to for mastering linear relationships, packed with everything you need for the AP SAT (Digital) exam. Let's dive in!

Understanding Linear Relationships

Linear relationships are all about that straight-line action! They help us connect real-world scenarios to math equations, showing how things change at a constant rate. Think of it as your math superpower for everyday life. Let's break it down:

Key Concept

Slope: The Rate of Change

  • What it is: Slope (often represented by 'm') shows how much the dependent variable (y) changes for every one unit increase in the independent variable (x).
  • Real-world examples:
    • Car rental: Slope = cost per mile driven
    • Business: Slope = profit increase per unit sold
  • Types of slopes:
    • Positive slope: Direct relationship (as x increases, y increases)
    • Negative slope: Inverse relationship (as x increases, y decreases)
  • Steeper slope: Faster rate of change

Key Concept

Y-intercept: The Starting Point

  • What it is: The y-intercept (often represented by 'b') is the value of the dependent variable (y) when the independent variable (x) is zero.
  • Real-world examples:
    • Car rental: Y-intercept = fixed base rental fee
    • Savings account: Y-intercept = initial deposit amount
    • Note: Sometimes, a y-intercept might be a theoretical starting point if x=0 isn't practical.

Modeling with Linear Equations

Setting Up Equations: T...

Question 1 of 11

A phone plan charges a base fee plus a cost per gigabyte of data used. If the total cost increases as more data is used, what type of slope does this relationship have? πŸ“ˆ

Negative slope

Zero slope

Positive slope

Undefined slope