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 167

Identify the y-intercept. Then find another point that lies on the grid.

y=1/2x+1

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.

y-intercept

The y-intercept is the y-value where the line crosses the y-axis.
Y-intercept of the function y=0.5*x+1 located at (0,1)

We can see that the function intercepts the y-axis at (0, 1). This means that the value of b is 1. y= mx+ 1

Slope

To find the slope, we will trace along the line on the given graph until we find a lattice point, which is a point that lies perfectly on the grid lines. In doing so, we can identify the slope m using the rise and run of the graph.

slope of the function y = 0.5*x+1 using the points (0,1) and (4,3)

Here we have identified (4,3) as our other point. Traveling to this point from the y-intercept requires that we move 4 steps horizontally in the positive direction and 2 steps vertically in the positive direction. rise/run=2/4 ⇔ m= 1/2

Writing the Equation

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