Linear Equations
8-4The Slope-Intercept Form of a Linear Equation
Overview
y = mx + b: m is slope, b is y-intercept.
Key ideas
- Read slope and intercept directly from the equation.
- Graph: plot (0, b), then use slope to find more points.
- Rewrite equations in this form to compare lines.
Worked examples
Example 1
Problem. Identify slope and y-int: y = 3x − 4.
Solution. m = 3, b = −4
Example 2
Problem. Graph y = −x + 2.
Solution. y-int 2, slope −1: (0,2) → (1,1).
Practice
Try each one. Click Show answer when ready.
- 1.
Identify slope and y-int of y = (1/2)x + 3.
- 2.
Rewrite 2x + y = 5 in slope-intercept form.
- 3.
Slope and y-int of y = −4x.
Challenge problems
A little tougher — great for test prep. Click Show answer when ready.
- 1.
Write in slope-intercept form: 3x − 2y = 8.
- 2.
Find the slope and y-intercept of 4x + 5y = 10.