SOLUTION: (2,7) and (-4,-3)

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Question 952835: (2,7) and (-4,-3)
Answer by MathLover1(20849) 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 (2,7) and (-4,-3)


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 (2,7) and (x%5B2%5D,y%5B2%5D) is the second point (-4,-3))


m=%28-3-7%29%2F%28-4-2%29 Plug in y%5B2%5D=-3,y%5B1%5D=7,x%5B2%5D=-4,x%5B1%5D=2 (these are the coordinates of given points)


m=+-10%2F-6 Subtract the terms in the numerator -3-7 to get -10. Subtract the terms in the denominator -4-2 to get -6




m=5%2F3 Reduce



So the slope is

m=5%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-7=%285%2F3%29%28x-2%29 Plug in m=5%2F3, x%5B1%5D=2, and y%5B1%5D=7 (these values are given)



y-7=%285%2F3%29x%2B%285%2F3%29%28-2%29 Distribute 5%2F3


y-7=%285%2F3%29x-10%2F3 Multiply 5%2F3 and -2 to get -10%2F3

y=%285%2F3%29x-10%2F3%2B7 Add 7 to both sides to isolate y


y=%285%2F3%29x%2B11%2F3 Combine like terms -10%2F3 and 7 to get 11%2F3 (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 (2,7) and (-4,-3) is:y=%285%2F3%29x%2B11%2F3


The equation is now in y=mx%2Bb form (which is slope-intercept form) where the slope is m=5%2F3 and the y-intercept is b=11%2F3


Notice if we graph the equation y=%285%2F3%29x%2B11%2F3 and plot the points (2,7) and (-4,-3), we get this: (note: if you need help with graphing, check out this solver)


Graph of y=%285%2F3%29x%2B11%2F3 through the points (2,7) and (-4,-3)


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