SOLUTION: Find an equation of the line passing through the pair of points. Write the equation in the form Ax+By=C. (-4,5), (-5,-9)

Algebra ->  Linear-equations -> SOLUTION: Find an equation of the line passing through the pair of points. Write the equation in the form Ax+By=C. (-4,5), (-5,-9)      Log On


   

Question 881268: Find an equation of the line passing through the pair of points. Write the equation in the form Ax+By=C. (-4,5), (-5,-9)
Found 2 solutions by lwsshak3, josgarithmetic:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Find an equation of the line passing through the pair of points. Write the equation in the form Ax+By=C. (-4,5), (-5,-9)
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Form of equation for a line: y=mx+b, m=slope, b=y-intercept
slope=∆y/∆x=(-9-5)/(-5-(-4))=-14/-1=14
equation: y=14x+b
solve for b using coordinates of one given point (-4,5)
5=14*-4+b
b=61
equation: y=14x+61
or
14x-y=-61

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Slope of the equation in standard form is -%28A%2FB%29. You can find the constant C using this slope and either of the two given points.

Slope: %285-%28-9%29%29%2F%28-4-%28-5%29%29=%2814%29%2F1.
This slope means you could choose 14=-%28A%2FB%29 , B=-1 and A=14. A=-14B.

Ax%2BBy=C
14x-1%2Ay=C
highlight_green%2814x-y=C%29
Choose either point, example, taking (-4,5), find C.
14%28-4%29-%285%29=C
-56-5=C
highlight_green%28-61=C%29
-
Putting the pieces together as the equation wanted,
highlight%2814x-y=-61%29
OR
highlight%28-14x%2By=61%29, same thing, just multiplied BOTH sides by negative 1.