More on Slope

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Section 2.4 More on Slope

Parallel and Perpendicular Lines

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Section 2.4 More on Slope

y = 2x+7

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Section 2.4 More on Slope

Parallel Lines

Find a line parallel to - x 6 y 8 and passing through (-2,3).

-x 6 y 8

Solve for y

6y x 8

1

4

1

y x

Use the slope

6

3

6

1 y 3 ( x 2)

Substitute into the point-slope form

6

1

1

y 3 x

6

3

1

1 y x 3

6

3

1

10 y x

6

3

4

Section 2.4 More on Slope

Example

Write the equation in slope-intercept form for a line that is parallel to 3x - 4y = 12 and passing through

(5,2).

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Section 2.4 More on Slope

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Section 2.4 More on Slope

Perpendicular Lines

Find a line perpendicular to - x 6 y 8 and passing through (-2, 3).

-x 6 y 8

Solve for y

6y

*…show more content…*

What does this slope represent?

x

x years after 1997

The percent of US adult cigarette smokers is decreasing by .52 percent each year. The change is consistent each year.

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Section 2.4 More on Slope

The Average Rate of Change of a Function

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Section 2.4 More on Slope

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Section 2.4 More on Slope

The Average Rate of Change of a

Function

If the graph of a function is not a straight line, the average rate of change between any two points is the slope of the line containing the two points. This line is called a secant line. y

( x2 , f ( x2 ))

f ( x2 ) f ( x1 ) x2 x1

Secant line

( x1, f ( x1))

x

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Section 2.4 More on Slope

Find the equation of the line that is parallel to 3x - 5 y 8 and passes through the point (4,-5).

(a)

(b)

(c)

(d)

3

7

y x

5

5

3

y x9

5

5

7

y - x

3

5

3

37 y x

5

5

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Section 2.4 More on Slope

Find the equation of the line that is perpendicular to 8 x - 3 y 6 and passes through (-1,3).

(a)

(b)

(c)

(d)

3 y x6

8

8

21

y - x

3

8

3

21 y - x

8

8

8

y - x6

3

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Section 2.4 More on