Common Core: 8th Grade Math

Explore the foundational concepts of mathematics, including algebra, geometry, and data analysis, essential for 8th-grade students.

Basic Concepts

Linear Equations and Functions

Understanding Relationships

In 8th grade math, a huge focus is on linear equations and functions. A linear equation is like a rule that creates a straight line when you graph it. The standard form is \( y = mx + b \), where \( m \) is the slope (how steep the line is) and \( b \) is the y-intercept (where the line crosses the y-axis).

Why Are They Useful?

Linear equations help us model and predict all sorts of real-world things, from budgeting to tracking sports scores. When we write an equation for a situation, we can use it to answer "what if" questions.

Parts of a Linear Function

  • Slope (\( m \)): Shows how much \( y \) changes for each step in \( x \)
  • Y-intercept (\( b \)): Where the line hits the y-axis

Graphing is Powerful!

By graphing the equation, you get a visual of how one variable changes with another. It's like drawing a map of a relationship!

Key Formula

\[y = mx + b\]

Examples

  • A cell phone plan charges $10 each month plus $5 for every gigabyte of data. The total cost (\( y \)) can be written as \( y = 5x + 10 \).

  • If a car travels at a constant speed, its distance (\( y \)) over time (\( x \)) can be expressed as \( y = 60x \) if it goes 60 miles per hour.

In a Nutshell

Linear equations describe straight-line relationships and help us predict outcomes in real life.

Key Terms

Slope
The rate of change between two variables in a linear equation.
Y-intercept
The value of \( y \) when \( x = 0 \); where the line crosses the y-axis.