SOLUTION: Find the foci of the ellipse 5x2+7y2+10x-28y-2=0

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Question 1034016: Find the foci of the ellipse 5x2+7y2+10x-28y-2=0
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
We have to get this into standard form...so from
5x%5E2%2B7y%5E2%2B10x-28y-2=0
we will some factoring and completing the squares...we get
5%28x%5E2+%2B+2x%29+%2B+7%28y%5E2+-+4y%29+=+2
5%28x%5E2+%2B+2x+%2B+1%29+%2B+7%28y%5E2+-+4y+%2B+4%29+=+2+%2B+5+%2B+28
5%28x%2B1%29%5E2+%2B+7%28y-2%29%5E2+=+35
%28x%2B1%29%5E2+%2F+%2835%2F5%29+%2B+%28y-2%29%5E2+%2F+%2835%2F7%29+=+1
Here a^2 = 7 and b^2 = 5...
You need to find
(c,0) and (-c,0)
where
c^2 = a^2 - b^2
Take it from here...