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The distance between the points (a,21) and (4,7) is 10*sqrt(2) Find the sum of all possible values of a

 Mar 16, 2020
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Distance formula

 

sqrt ( (a-4)^2  + (21-7)^2  )   =  10 sqrt 2

sqrt ( (a^2-8a+16) + 196 ) = 10 sqrt 2

          a^2-8a+16 +196     = 200

          a^2-8a + 12            =0                      either factor (in your head ) or use quadratic formula to find the TWO values of 'a'

 Mar 16, 2020

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