SOLUTION: write the equation of the best-fit line in slope intercept form using the two data points given (9,-3)(5,-5)

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Question 350956: write the equation of the best-fit line in slope intercept form using the two data points given (9,-3)(5,-5)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

First let's find the slope of the line through the points and


Note: is the first point . So this means that x%5B1%5D=9 and y%5B1%5D=-3.
Also, is the second point . So this means that x%5B2%5D=5 and y%5B2%5D=-5.


m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula.


m=%28-5--3%29%2F%285-9%29 Plug in y%5B2%5D=-5, y%5B1%5D=-3, x%5B2%5D=5, and x%5B1%5D=9


m=%28-2%29%2F%285-9%29 Subtract -3 from -5 to get -2


m=%28-2%29%2F%28-4%29 Subtract 9 from 5 to get -4


m=1%2F2 Reduce


So the slope of the line that goes through the points and is m=1%2F2


Now let's use the point slope formula:


y-y%5B1%5D=m%28x-x%5B1%5D%29 Start with the point slope formula


y--3=%281%2F2%29%28x-9%29 Plug in m=1%2F2, x%5B1%5D=9, and y%5B1%5D=-3


y%2B3=%281%2F2%29%28x-9%29 Rewrite y--3 as y%2B3


y%2B3=%281%2F2%29x%2B%281%2F2%29%28-9%29 Distribute


y%2B3=%281%2F2%29x-9%2F2 Multiply


y=%281%2F2%29x-9%2F2-3 Subtract 3 from both sides.


y=%281%2F2%29x-15%2F2 Combine like terms. note: If you need help with fractions, check out this solver.


So the equation that goes through the points and is y=%281%2F2%29x-15%2F2


If you need more help, email me at jim_thompson5910@hotmail.com

Also, feel free to check out my tutoring website

Jim