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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)
      (Show Source): 
You can put this solution on YOUR website! Find the equation of the line containing the points (4,-2) and (1,3). -------
 Don't put a space after the comma.
 ---
 It's not "the equation" it's an equation.
 ---
 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|
========
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.
 =====================
 You can check for mistakes.
 Sub for x & y in each equation.
 
Answer by ikleyn(52879)
      (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  ( ,  )  and  (  ,  )  is
        m =  .
    Substitute the given data  = 4,  = -2,  = 1,  = 3  into the basic formula
        m =  =  =  .
Next, write an equation of the line having the slope  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 =  ,  a = 4,  b = -2,  and you will get
        y - (-2) =  ,   or, equivalently,
        y + 4    =  .
        Having the equation in this form, you can convert it to any other equivalent form you want.----------------
 
 See the lesson
 - Equation for a straight line in a coordinate plane passing through two given points
 in this site.
 
 
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