SOLUTION: Write an equation for the line containing the indicated points. (-6,-6) and (-3,1)

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Question 124795This question is from textbook Algebra 2
: Write an equation for the line containing the indicated points.
(-6,-6) and (-3,1)
This question is from textbook Algebra 2

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (-6,-6) and (-3,1)


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula (note: (x%5B1%5D,y%5B1%5D) is the first point (-6,-6) and (x%5B2%5D,y%5B2%5D) is the second point (-3,1))


m=%281--6%29%2F%28-3--6%29 Plug in y%5B2%5D=1,y%5B1%5D=-6,x%5B2%5D=-3,x%5B1%5D=-6 (these are the coordinates of given points)


m=+7%2F3 Subtract the terms in the numerator 1--6 to get 7. Subtract the terms in the denominator -3--6 to get 3



So the slope is

m=7%2F3





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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 (x%5B1%5D,y%5B1%5D) is one of the given points


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


y--6=%287%2F3%29%28x--6%29 Plug in m=7%2F3, x%5B1%5D=-6, and y%5B1%5D=-6 (these values are given)



y%2B6=%287%2F3%29%28x--6%29 Rewrite y--6 as y%2B6



y%2B6=%287%2F3%29%28x%2B6%29 Rewrite x--6 as x%2B6



y%2B6=%287%2F3%29x%2B%287%2F3%29%286%29 Distribute 7%2F3


y%2B6=%287%2F3%29x%2B14 Multiply 7%2F3 and 6 to get 42%2F3. Now reduce 42%2F3 to get 14

y=%287%2F3%29x%2B14-6 Subtract 6 from both sides to isolate y


y=%287%2F3%29x%2B8 Combine like terms 14 and -6 to get 8

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Answer:



So the equation of the line which goes through the points (-6,-6) and (-3,1) is:y=%287%2F3%29x%2B8


The equation is now in y=mx%2Bb form (which is slope-intercept form) where the slope is m=7%2F3 and the y-intercept is b=8


Notice if we graph the equation y=%287%2F3%29x%2B8 and plot the points (-6,-6) and (-3,1), we get this: (note: if you need help with graphing, check out this solver)


Graph of y=%287%2F3%29x%2B8 through the points (-6,-6) and (-3,1)


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