SOLUTION: if x/3=y/5=z/7 then (z2-x2+y2)/2y2=

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Question 761562: if x/3=y/5=z/7 then (z2-x2+y2)/2y2=
Answer by ramkikk66(644) About Me  (Show Source):
You can put this solution on YOUR website!
I think you are asking for the value of the expression
%28z%5E2+-+x%5E2+%2B+y%5E2%29%2F%282%2Ay%5E2%29
Given that x/3=y/5=z/7
First, we express x and z in terms of y
x%2F3+=+y%2F5 Therefore x+=+3%2Ay%2F5
z%2F7+=+y%2F5 Therefore z+=+7%2Ay%2F5
Now in the given expression, substitute for x and z in terms of y
%28z%5E2+-+x%5E2+%2B+y%5E2%29%2F%282%2Ay%5E2%29
=
%28%287%2Ay%2F5%29%5E2+-+%283%2Ay%2F5%29%5E2+%2B+y%5E2%29%2F%282%2Ay%5E2%29
=
%2849%2Ay%5E2%2F25+-+9%2Ay%5E2%2F25+%2B+y%5E2%29%2F%282%2Ay%5E2%29
=
65%2Ay%5E2%2F%2825%2A2%2Ay%5E2%29
=
13%2F10

:)