SOLUTION: Write the point slope form of the equation of the line that passes through the points (-3,5) and (-1,4)

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Write the point slope form of the equation of the line that passes through the points (-3,5) and (-1,4)      Log On


   



Question 1062200: Write the point slope form of the equation of the line that passes through the points (-3,5) and (-1,4)
Found 2 solutions by Alan3354, Edwin McCravy:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Same problem, different numbers.
=============================
Write the point slope form of the equation of the line that passes through the points (5,-9) and (-6,1)
---
slope = m = (1--9)/(-6-5) = 10/-11 = -10/11
-------------------
Form:: y = mx + b
Solve for "b"::
-9 = (-10/11)5 + b
-------
-9 + (50/11) = b
----
-99/11 + 50/11 = -49/11
-----
Equation:
y = (-10/11)x - (49/11)
-------------------
Cheers,
Stan H.
-------------

Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
Write the point slope form of the equation of the
line that passes through the points (-3,5) and (-1,4)


Let's plot the points (-3,5) and (-1,4), and draw a line
through them (in green):



Now we use the slope formula:

m%22%22=%22%22%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29

m%22%22=%22%22%28%284%29-%285%29%29%2F%28%28-1%29-%28-3%29%29

m%22%22=%22%22%284-5%29%2F%28-1%2B3%29

m%22%22=%22%22%28-1%29%2F2

m%22%22=%22%22-1%2F2

Now use the point-slope form:

y-y%5B1%5D%22%22=%22%22m%28x-x%5B1%5D%29

y-5%22%22=%22%22expr%28-1%2F2%29%28x-%28-3%29%5E%22%22%29

That's the point slope form. But it can be simplified 
to the slope-intercept form y = mx+b

y-5%22%22=%22%22expr%28-1%2F2%29%28x%2B3%29

y-5%22%22=%22%22expr%28-1%2F2%29x-3%2F2

y%22%22=%22%22expr%28-1%2F2%29x-3%2F2%2B5

y%22%22=%22%22expr%28-1%2F2%29x-3%2F2%2B10%2F2

y%22%22=%22%22expr%28-1%2F2%29x%2B7%2F2

Edwin