MAT 150 Unit 16a

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MAT 150 Unit 16a

• Ch 9 2
• Alternate Methods of Graphing Linear Equations

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Graphing Lines

• Using the slope intercept method

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Slope
Slope describes the direction of a line.
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Slope

• If x1 ? x2, the slope of the line through the
  distinct points (x1, y1) and (x2, y2) is
• m rise change in y y2- y1
• run change in x x2- x1

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Find the slope between (-3, 6) and (5, 2)
(-3, 6)
(5, 2)
Rise
-4
-1


Run
8
2
6
From these results we can see...

• The slope of a vertical line is undefined.
• (also called NO SLOPE)
• The slope of a horizontal line is 0.

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Find the slope of the line 4x - y 8
Here is an easier way
Solve for y.
m 4
When the equation is solved for y the coefficient
of x is the slope!!
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Sign of the Slope
Which have a negative slope?
Which have a positive slope?
Red Light Blue Blue
Green White
No slope
Zero Slope
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Linear Equations (y mx b)

• b y-intercept
• plot (0,b) to get your first point
• m slope
• written as a fraction slope rise/run
• Lean right if positive
• Lean left if negative

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Linear Equations (y mx b)
b 2 (y-intercept) plot (0,2)
y -1/2 x 2
m -1/2 (slope rise/run) negative leans
left plot up 1, left 2 plot down 1, right 2
connect the points
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Linear Equations (y mx b)
b -3 (y-intercept) plot (0,-3)
y 1/3 x - 3
m 1/3 (slope rise/run) positive leans
right plot up 1, right 3 plot down 1, left 3
connect the points