SOLUTION: hey, this problem is also giving me trouble: if y varies inversely as x and y=-5 when x=12.5, find x when y=15. thanks

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Question 85309: hey,

this problem is also giving me trouble: if y varies inversely as x and y=-5 when x=12.5, find x when y=15.

thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
There's a thing called the 'constant of variation'
Write the relation like this:
y+=+k%281%2Fx%29 This says "Y varies inversely with x with k being the
constant of variation
-5+=+k%281%2F12.5%29 Now find k
k+=+%28-5%29%2812.5%29
k+=+-+62.5
Now finish the problem
15+=+k%281%2Fx%29
15+=+%28-62.5%29%281%2Fx%29
x+=+-%2862.5%2F15%29
x+=+-4.167