SOLUTION: Using point-slope form,find an equation for the line that contains the points (-2,6) and (10,-5)

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Question 101866: Using point-slope form,find an equation for the line that contains the points
(-2,6) and (10,-5)

Answer by edjones(8007) 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 (-2,6) and (10,-5)


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 (-2,6) and (x%5B2%5D,y%5B2%5D) is the second point (10,-5))


m=%28-5-6%29%2F%2810--2%29 Plug in y%5B2%5D=-5,y%5B1%5D=6,x%5B2%5D=10,x%5B1%5D=-2 (these are the coordinates of given points)


m=+-11%2F12 Subtract the terms in the numerator -5-6 to get -11. Subtract the terms in the denominator 10--2 to get 12



So the slope is

m=-11%2F12





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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=%28-11%2F12%29%28x--2%29 Plug in m=-11%2F12, x%5B1%5D=-2, and y%5B1%5D=6 (these values are given)



y-6=%28-11%2F12%29%28x%2B2%29 Rewrite x--2 as x%2B2



y-6=%28-11%2F12%29x%2B%28-11%2F12%29%282%29 Distribute -11%2F12


y-6=%28-11%2F12%29x-11%2F6 Multiply -11%2F12 and 2 to get -22%2F12. Now reduce -22%2F12 to get -11%2F6

y=%28-11%2F12%29x-11%2F6%2B6 Add 6 to both sides to isolate y


y=%28-11%2F12%29x%2B25%2F6 Combine like terms -11%2F6 and 6 to get 25%2F6 (note: if you need help with combining fractions, check out this solver)



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Answer:



So the equation of the line which goes through the points (-2,6) and (10,-5) is:y=%28-11%2F12%29x%2B25%2F6


The equation is now in y=mx%2Bb form (which is slope-intercept form) where the slope is m=-11%2F12 and the y-intercept is b=25%2F6


Notice if we graph the equation y=%28-11%2F12%29x%2B25%2F6 and plot the points (-2,6) and (10,-5), we get this: (note: if you need help with graphing, check out this solver)


Graph of y=%28-11%2F12%29x%2B25%2F6 through the points (-2,6) and (10,-5)


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