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# Write an equation in point-slope form for the line through the given point with the given

+6
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7

Write an equation in point-slope form for the line through the given point with the given

slope.

1. (10, –9); m = −2

2. (9, –8); m = 5/6

3. (10, 6); m = -2/3

4. (7, 10); m = - 1/2

5.  (–1, 2); m = 1

6. A line passes through (2, –1) and (8, 4). Write an equation for the line in point-slope form.

7. A line passes through (4, 3) and (10, 10). Write an equation for the line in point-slope form.

8. A line passes through (–5, –9) and (2, –6). Write an equation for the line in point-slope form.

9. A line passes through (–1, 3) and (10, 9). Write an equation for the line in point-slope form.

10. A line passes through (–7, –3) and (4, 4). Write an equation for the line in point-slope form.

Is the relationship shown by the data linear? If so, model the data with an equation.

11.

 X Y –9 -2 -5 -7 -1 -12 3 -17

12.

 X Y 9 1 15 3 21 5 27 7

13.

 X Y -9 -3 -3 -2 3 0 9 1

14.

 X Y 5 -2 11 -1 17 0 23 1

15.

 X Y -5 1 -1 0 3 -1 7 -2
Sep 17, 2015

#4
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6. A line passes through  (2,    –1) and   (8,    4). Write an equation for the line in point-slope form.

(  x1,  y1)         (x2 , y2)

Use the above to find the slope, m,  which is given by  :

m =  [ y2 - y1] / [ x2 - x1]    =    [4 - (-1)] / [ 8 - 2)  =  5/6

Then..... just use one  of the points (either one, doesn't matter) and do what we just did in 1 -5

y - 4 = (5/6)(x - 8)

This example should get you through  number 10

I'll finish the rest in a little while   Sep 17, 2015

#1
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...............................................................................................

Sep 17, 2015
edited by CPhill  Sep 17, 2015
edited by CPhill  Sep 17, 2015
#2
+10

Sorry, Haley.....they wanted point-slope form....here we go

These examples should cover every problem  3 - 5.......

Point-slope form   .......y - y1 = m(x - x1)

1. (10, –9); m = −2    →     y - (-9)= -2(x - 10)

2. (9, –8); m = 5/6  →        y - (-8)  = (5/6) (x - 9)   Sep 17, 2015
#3
0

Sep 17, 2015
#4
+10

6. A line passes through  (2,    –1) and   (8,    4). Write an equation for the line in point-slope form.

(  x1,  y1)         (x2 , y2)

Use the above to find the slope, m,  which is given by  :

m =  [ y2 - y1] / [ x2 - x1]    =    [4 - (-1)] / [ 8 - 2)  =  5/6

Then..... just use one  of the points (either one, doesn't matter) and do what we just did in 1 -5

y - 4 = (5/6)(x - 8)

This example should get you through  number 10

I'll finish the rest in a little while   CPhill Sep 17, 2015
#6
+10

11.

X     Y

–9   -2

-5   -7

-1  -12

3   -17

OK Haley ....this isn't difficult....just time consuming

If the differences in the x's and y's are constant, we have a line....if not, we don't

Notice that the difference in one x to another reading downward is +4

For example   -9 + 4   = -5      and -5 + 4 = -1    and -1 + 4 = 3   ...... etc.

And the difference in one y to another reading downward is also constant = -5

For example -2 - 5 = -7   and -7 - 5  = -12 ........etc

So...if we have a line......as we did in number 6.....use any two of the points to find the slope and then write the equation

For exampe in 11, we can use ( -9, -2) and (-5, -7)

( x1, y1 )    (x2, y2)

The slope = m = [y2 - y1] / [ x2 - x1]   = [-7 - (-2)] / [-5 - (-9)]  =  -5 / 4

And the equation .....in point-slope form is

y - (-7)  = (-5/4) [ x - (-5)]        [remember that we can use any point on the line in this equation]

The rest are similar.........if the differences in x's and y's are not constant......we don't have a line so don't worry about writing an equation in that case

[13 is not a line...the y's are not constant......don't worry about it....!!! ]   Sep 17, 2015
#7
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Thanks but I don't understand 6- 10 still

Sep 17, 2015