SOLUTION: help me find the standard equation of the circle passing thru the point (-3,1) and containing the points of intersection of the circles x^2 + y^2 + 5x = 1 & x^2 + y^2 + y = 7. The

Algebra ->  Circles -> SOLUTION: help me find the standard equation of the circle passing thru the point (-3,1) and containing the points of intersection of the circles x^2 + y^2 + 5x = 1 & x^2 + y^2 + y = 7. The       Log On


   

Question 876661: help me find the standard equation of the circle passing thru the point (-3,1) and containing the points of intersection of the circles x^2 + y^2 + 5x = 1 & x^2 + y^2 + y = 7. The soln: (x+5/9)^2 + (y+7/18)^2 = 569/100. thank you!
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
help me find the standard equation of the circle passing thru the point (-3,1) and containing the points of intersection of the circles x^2 + y^2 + 5x = 1 & x^2 + y^2 + y = 7. The soln: (x+5/9)^2 + (y+7/18)^2 = 569/100. thank you!
That is not the correct solution:

That's because %28x%2B5%2F9%29%5E2+%2B+%28y%2B7%2F18%29%5E2+=+569%2F100 

does not pass through (-3,1)

Substitute x=-3, y=1 in 

%28x%2B5%2F9%29%5E2+%2B+%28y%2B7%2F18%29%5E2+=+569%2F100

%28-3%2B5%2F9%29%5E2+%2B+%281%2B7%2F18%29%5E2+=+569%2F100

%28-27%2F9%2B5%2F9%29%5E2+%2B+%2818%2F18%2B7%2F18%29%5E2+=+569%2F100

%28-22%2F9%29%5E2+%2B+%2825%2F18%29%5E2+=+569%2F100

484%2F81+%2B+625%2F324+=+569%2F100

1936%2F324%2B625%2F324%29=+569%2F100

2561%2F324+=+589%2F100

Since the answer given above doesn't pass through (-3,1),
there has to be a typo somewhere.  Check the problem
again very carefully for a sign error or some other small
error.  Type it very carefully in the thank-you note, and I'll 
get back to you.

Edwin