SOLUTION: Write the equation of the line passing through (–6, –9) and (1, –9).

Algebra ->  Coordinate-system -> SOLUTION: Write the equation of the line passing through (–6, –9) and (1, –9).      Log On


   



Question 117206:
Write the equation of the line passing through (–6, –9) and (1, –9).

Found 2 solutions by jim_thompson5910, checkley71:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
First lets find the slope through the points (-6,-9) and (1,-9)

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula (note: is the first point (-6,-9) and is the second point (1,-9))

m=%28-9--9%29%2F%281--6%29 Plug in y%5B2%5D=-9,y%5B1%5D=-9,x%5B2%5D=1,x%5B1%5D=-6 (these are the coordinates of given points)

m=+0%2F7 Subtract the terms in the numerator -9--9 to get 0. Subtract the terms in the denominator 1--6 to get 7


m=0 Reduce

So the slope is
m=0

------------------------------------------------


Now let's use the point-slope formula to find the equation of the line:



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

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

y--9=%280%29%28x--6%29 Plug in m=0, x%5B1%5D=-6, and y%5B1%5D=-9 (these values are given)


y%2B9=%280%29%28x--6%29 Rewrite y--9 as y%2B9


y%2B9=%280%29%28x%2B6%29 Rewrite x--6 as x%2B6


y%2B9=0x%2B%280%29%286%29 Distribute 0

y%2B9=0x%2B0 Multiply 0 and 6 to get 0%2F0. Now reduce 0%2F0 to get 0

y=0x%2B0-9 Subtract 9 from both sides to isolate y

y=0x-9 Combine like terms 0 and -9 to get -9


y=-9 Remove the zero term
------------------------------------------------------------------------------------------------------------
Answer:


So the equation of the line which goes through the points (-6,-9) and (1,-9) is:y=-9

The equation is now in y=mx%2Bb form (which is slope-intercept form) where the slope is m=0 and the y-intercept is b=-9

Notice if we graph the equation y=-9 and plot the points (-6,-9) and (1,-9), we get this: (note: if you need help with graphing, check out this solver)

Graph of y=-9 through the points (-6,-9) and (1,-9)

Notice how the two points lie on the line. This graphically verifies our answer.

Answer by
checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
slope=(-9+9)/(1+6)
slope=(0/7)
slope=0
now replace the line formula [Y=mX+b]
-9=0*-6+b
b=-9
SO THE EQUATION IS Y=-9.
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+Y+=+-9%29+ (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, Y = -9).