SOLUTION: Find an equation of the line that passes through the points 4,4 and 8,-2

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Question 357199: Find an equation of the line that passes through the points 4,4 and 8,-2
Found 3 solutions by Alan3354, mananth, neatmath:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Given 2 points example.
Find the equation of the line thru the points (2,1) and (3,5)
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This is a 2 step process. First find the slope of the line thru the points.
slope, m = diffy/diffx
m = (5-1)/(3-2)
m = 4
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Now use y = mx + b with either point to find b, the y-intercept.
y = mx + b
5 = 4*3 + b
b = -7
-------
y = mx + b
y = 4x - 7 is the answer.
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Another approach using determinants:
|x y 1|
|2 1 1| = 0
|3 5 1|
--------
x(1-5) - y(2-3) + 1(10-3) = 0
-4x + y + 7 = 0
y = 4x - 7
---------
For further assistance, or to check your work, email me via the thank you note
or at Moral Loophole@aol.com

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
4,4 and 8,-2
slope = y2-y1/x2-x1
slope = -6/4 = -3/2
...
y=mx+b
plug values of xy & m
4=-3/2*4+b
4=-6+b
b=10
...
the equation
y = -3x/2 +10
...
m.ananth@hotmail.ca

Answer by neatmath(302) About Me  (Show Source):
You can put this solution on YOUR website!

The easiest way to find this equation is to use point-slope form!

First we need to find the slope:

m=%28y2-y1%29%2F%28x2-x1%29

m=%28-2-4%29%2F%288-4%29

m=%28-6%29%2F4

m=-3%2F2

Then we can use the point-slope form: y-y1=m%28x-x1%29

We will use the first point (4,4) and m=-3/2

y-4=%28-3%2F2%29%2A%28x-4%29

y=-3x%2F2%2B%284%2A3%29%2F2%2B4

y=-3x%2F2%2B6%2B4

y=-3x%2F2%2B10

This is now in slope-intercept form, where we can easily see the slope is -3/2, and the y-intercept is (0,10).

I hope this helps!