Big Ideas Math Integrated I, 2016
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Big Ideas Math Integrated I, 2016 View details
1. Writing Equations in Slope-Intercept Form
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Exercise 3 Page 165

How can you find the slope by looking at a graph? Where can you find the y-intercept?

You can find the key components by looking at the graph. See solution.

Practice makes perfect
The equation of a line is most commonly written in slope-intercept form: y=mx+b, where m is the slope and b is the y-intercept. We can look at the graph of any line on a coordinate plane and find these pieces of information. In general, the process would look as it does on the graph below.

Let's look at this exact same graph with the numbers included so that we can have a more concrete example.

We can see that the y-intercept is located at y=-2 so that is our value for b. The slope is: Rise/Run=2/4 ⇒ m=1/2. Our final equation of the line is then y=1/2x-2.