Slope-Intercept Formof a Linear Equation

Is this a linear equation? 3x + 2y = 6

323

xy

Let’s Graph! How would you graph the first

equation?

How would you graph the second equation?

A linear equation in the form of y = mx + b is in slope-intercept form.

When a linear equation is solved for y, you can identify the slope and the y-intercept.

Examples: Write an equation of the line whose slope is and whose y-intercept is -6.

Let m = slope and b = y-intercept.

y = x – 6

41

41

Write an equation of the line shown in the graph.

Writing Equations in Slope-Intercept Form

4x – 6y = 3 Find the slope and y-intercept.

12x = -3y + 24Find the slope and y-intercept

Recall that Ax + By = C is the standard form of a linear equation. Solve this equation for y.

Write 8x – 4y = 12 in slope-intercept form.

Graphing Linear Equations Set up a table of values. Quick graphs using intercepts

(standard form) Slope and y-intercept

Graph y = 0.5x – 7 Graph 5x + 4y = 8

Real Life Examples of Slope-Intercept Form

Plumber A charges a flat rate of $25 plus $30 an hour

Define the variables and write an equation for Plumber A

Plumber B charges a flat rate of $40 plus $25 an hour.

Define the variables and write an equation for Plumber B

Graph both equations.