Write an equation in slope-intercept form for the line that passes through (-1,2) and (3,-7)
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Write an equation in slope-intercept form for the line that passes through (-1,2) and (3,-7)

[From: ] [author: ] [Date: 11-08-15] [Hit: ]
change in y,change in x, -1 → 3 is up 4 ∙ ∙ ∙ ∙ ∙ ∙ so slope is -9/4,b= 13/4 so y = -5x/4 + 13/4-None of the above.........
a. y = 5/4 x - 3/4
b. y = -4/5 x - 6/5
c. y = 4/5 x - 6/5
d. y = -5/4 x - 13/4

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Calculate the Slope:

m = Δy/ Δx

m = -2-(-7)/-1-3

m = 5/-4

Now we can solve for the y-intercept by plugging any 'x' and 'y' values of the given coordinates and the value of 'm.' For this example, we'll use the first pair of coordinates (-1, 2):

y = mx + b

-2 = -5/4*-1 + b

2 = -5/4 + b

2 + 5/4 = b

13/4 = b

The equation in slope intercept form is y = -9/4x + 13/4 or d.

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whoever wrote the list of answers made the mistake of adding the y coordinates instead of subtracting them to get the change in y.

change in y, 2 → -7 is down 9
change in x, -1 → 3 is up 4 ∙ ∙ ∙ ∙ ∙ ∙ so slope is -9/4, which none of the answers have

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slope = (-7- -2) / (3- - 1) = -5/4

y = -5x/4 + b

2 = 5/4 + b

b= 13/4 so y = -5x/4 + 13/4

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None of the above...y=(9/4)-1/4
1
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