Big Ideas Math Integrated I, 2016
BI
Big Ideas Math Integrated I, 2016 View details
1. Writing Equations in Slope-Intercept Form
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Exercise 9 Page 169

Identify the y-intercept. Use the two given points to calculate the slope.

y=1/3x+2

Practice makes perfect

Equations written in slope-intercept form follow a specific format. y= mx+ b In this form, m is the slope and b is the y-intercept. We need to identify these values using the graph and the two given points.

y-intercept

The y-intercept is the y-value where the line crosses the y-axis.
Y-intercept

We can see that the function intercepts the y-axis at (0, 2). This means that the value of b is 2. y= mx+ 2

Slope

To find the slope, we will consider the two given points and identify the slope m using the rise and run of the graph.

Slope

Here we have (3,3) as our other given point. Traveling from the y-intercept to this point requires that we move 3 steps horizontally in the positive direction and 1 step vertically in the positive direction. rise/run=1/3 ⇔ m= 1/3

Writing the Equation

Now that we have the slope and the y-intercept, we can write our final equation. y= 1/3x+ 2