SOLUTION: Find the equation of the line containing the points (4, -2) and (1, 3).

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Question 1142403: Find the equation of the line containing the points (4, -2) and (1, 3).
Found 2 solutions by Alan3354, ikleyn:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Find the equation of the line containing the points (4,-2) and (1,3).
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Don't put a space after the comma.
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It's not "the equation" it's an equation.
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There's more than 1 way to find them.
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Find the slope, m
m = diffy/diffx = 5/-3 = -5/3
Then, x-x1 = m*(y-y1) where (x1,y1 is either point.
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x-1 = (-5/3)*(y-3)
That's an equation.
1-x = (5y/3) - 5
That's an equation.
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|x   y   1|
|4  -2   1| = 0
|1   3   1|
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x*(-2*1 - 3*1) - y*(4*1 - 1*1) + 1*(4*3 - 1*-2) = 0
-5x - 3y + 14 = 0

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That's an equation.
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You can check for mistakes.
Sub for x & y in each equation.

Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
.
First, calculate the slope.


    The formula for the slope of a straight line passing through two given points  (x%5B1%5D,y%5B1%5D)  and  (x%5B2%5D,y%5B2%5D)  is
        m = %28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29.

    Substitute the given data  x%5B1%5D = 4,  y%5B1%5D = -2,  x%5B2%5D = 1, y%5B2%5D = 3  into the basic formula

        m = %283-%28-2%29%29%2F%281-4%29 = 5%2F%28-3%29 = -5%2F3.


Next, write an equation of the line having the slope  -5%2F3  and passing through the given point (4,-2).


    An equation of a straight line in a coordinate plane which has the slope m and passes through the given point  P = (a,b)  is 

        y - b = m*(x-a).     

    Substitute here  m = -5%2F3,  a = 4,  b = -2,  and you will get

        y - (-2) = %28-5%2F3%29%2A%28x-4%29,   or, equivalently,


        y + 4    = %28-5%2F3%29%2A%28x-4%29.


        Having the equation in this form, you can convert it to any other equivalent form you want.

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See the lesson
    - Equation for a straight line in a coordinate plane passing through two given points
in this site.