Big Ideas Math: Modeling Real Life, Grade 8
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Big Ideas Math: Modeling Real Life, Grade 8 View details
5. Graphing Linear Equations in Standard Form
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Exercise 13 Page 171

What information can you learn from the slope-intercept form of an equation?

Practice makes perfect
Equations written in slope-intercept form follow a specific format. y= mx+ b In this form, m represents the slope of the line and b represents the y-intercept.

Identifying the Slope and y-intercept

Since the given equation is not in slope-intercept form, let's rewrite it so that it will be easier to identify the slope and y-intercept.
16x-4y=2
16x-4y-16x=2-16x
-4y=2-16x
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Simplify
-4y/-4=2/-4-16x/-4
4y/4=2/-4-16x/-4
4y/4=- 2/4-(- 16x/4)
4y/4=- 2/4+ 16x/4
y=- 2/4+4x
y=- 1/2+4x
y=4x-1/2
Below we have highlighted the slope m and y-intercept b. y= 4x - 1/2 ⇔ y= 4x+( - 1/2) The slope is 4. The y-intercept is - 12, so the graph crosses the y-axis at the point (0, - 12).

Graphing the Equation

A slope of 4 means that for every 1 unit we move in the positive horizontal direction, we move 4 units in the positive vertical direction. m= 4/1 ⇔ rise/run=4/1 To graph the equation, plot the y-intercept and then use the slope to find another point on the line.