SOLUTION: Write the equation of the line that passes through point (7, –13) with a slope of –3.

Algebra ->  Linear-equations -> SOLUTION: Write the equation of the line that passes through point (7, –13) with a slope of –3.      Log On


   



Question 98516: Write the equation of the line that passes through point (7, –13) with a slope of –3.
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

If you want to find the equation of line with a given a slope of -3 which goes through the point (7,-13), you can simply use the point-slope formula to find the equation:


---Point-Slope Formula---
y-y%5B1%5D=m%28x-x%5B1%5D%29 where m is the slope, and is the given point

So lets use the Point-Slope Formula to find the equation of the line

y--13=%28-3%29%28x-7%29 Plug in m=-3, x%5B1%5D=7, and y%5B1%5D=-13 (these values are given)


y%2B13=%28-3%29%28x-7%29 Rewrite y--13 as y%2B13


y%2B13=-3x%2B%28-3%29%28-7%29 Distribute -3

y%2B13=-3x%2B21 Multiply -3 and -7 to get 21

y=-3x%2B21-13 Subtract 13 from both sides to isolate y

y=-3x%2B8 Combine like terms 21 and -13 to get 8
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Answer:


So the equation of the line with a slope of -3 which goes through the point (7,-13) is:

y=-3x%2B8 which is now in y=mx%2Bb form where the slope is m=-3 and the y-intercept is b=8

Notice if we graph the equation y=-3x%2B8 and plot the point (7,-13), we get (note: if you need help with graphing, check out this solver)

Graph of y=-3x%2B8 through the point (7,-13)
and we can see that the point lies on the line. Since we know the equation has a slope of -3 and goes through the point (7,-13), this verifies our answer.

Answer by
stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Write the equation of the line that passes through point (7, –13) with a slope of –3.
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Form y=mx+b
You are given x, y, and m; solve for b asfollows:
-13 = -3*7 + b
8 = b
EQUATION:
y=-3x+8
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Cheers,
Stan H.