Assignment 18

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????O???|??z???assignment #019

019. `query 19

College Algebra

07-04-2008

?????M???????assignment #018

018. `query 18

College Algebra

07-04-2008

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13:21:55

2.4.30 (was 2.3.24). Slope 4/3, point (-3,2)

Give the three points you found on this line and explain how you obtained them.

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RESPONSE -->

The 4 points altogether are (-6, -2), (-3, 2), (0, 6) and (3, 10)

since the slope is 4/3, every rise of four also has a run of three, same with -4 and -3.

confidence assessment: 2

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13:22:18

STUDENT SOLUTION:

(-3,2) slope 4/3. Move 3 units in the x direction, 4 in the y direction to get

((-3+3), (2+4)), which simplifies to

(0,6)

(-3,2) slope 4/3 = -4/-3 so move -3 units in the x direction and -4 in the y direction to get

((-3-3), (2-4)) which simplifies to

(-6,-2)

From (0,6) with slope 4/3 we move 4 units in the y direction and 3 in the x direction to get

((0+3), (6+4)), which simplifies to

(3,10). The three points I obtained are

(-6,-2), (0,6), (3,10).

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RESPONSE -->

ok

self critique assessment: 3

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13:27:51

query 2.4.36 (was 2.3.30). Line thru (-1,1) and (2,2) **** Give the equation of the line and explain how you found the equation.

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RESPONSE -->

Using the slope formula (y2 - y1) / (x2 - x1)

1-2 / -1-2 = 1/3

Using the equation of a line y - y1 = m(x - x1)

y - 1 = 1/3 (x + 1)

y -1 = (1/3)x + 1/3

y = (1/3)x + 4/3

confidence assessment: 2

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13:28:00

STUDENT SOLUTION: The slope is m = (y2 - y1) / (x2 - x1) = (2-1)/(2- -1) = 1/3.

Point-slope form gives us

y - y1 = m (x - x1); using m = 1/3 and (x1, y1) = (-1, 1) we get

y-1=1/3(x+1), which can be solved for y to obtain

y = 1/3 x + 4/3.

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RESPONSE -->

ok

self critique assessment: 3

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13:33:40

2.4.46 (was 2.3.40). x-int -4, y-int 4 **** What is the equation of the line through the given points and how did you find the equation?

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RESPONSE -->

Using the slope formula (y2 - y1) / (x2 - x1)

(0 -4) / (-4 -0) = -4/-4 = 1

Using the equation of a line y - y1 = m(x - x1)

y - 0 = 1(x -4)

y = x-4

confidence assessment: 2

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13:34:37

STUDENT SOLUTION: The two points are (0, 4) and (4, 0). The slope is therefore m=rise / run = (4-0)/(0+4) = 1.

The slope-intercept form is therefore y = m x + b = 1 x + 4, simplifying to

y=x+4.

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RESPONSE -->

I didn't change the sign on the 4... understood.

self critique assessment:

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13:35:41

2.4.56 (was 2.4.48). y = 2x + 1/2. **** What are the slope and the y-intercept of your line and how did you find them?

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RESPONSE -->

1/2 is the y intercept, and 2 is the slope

confidence assessment: 2

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13:35:56

** the y intercept occurs where x = 0, which happens when y = 2 (0) + 1/2 or y = 1/2. So the y-intercept is (0, 1/2).

The slope is m = 2.**

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RESPONSE -->

understood

self critique assessment: 3

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assignment #018

018. `query 18

College Algebra

07-04-2008

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