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| Question 841777:  Please help me solve this problems:
 1.A circle whose centre lies on the line y=3x-1, touches both axes:
 find:
 (A) the equation of the circle
 (B) the points where the circle intersects the line 2y+x=1
 2.Find the equation of the circle which passes through the points (0,3), (-1,2) and (7,-4)
 3.A circle passes through the points (1,-15) and (-11,3). Its centre lies on the line 5y-12x+22=0. Find the coordinates of the centre, the radius and the equation of the circle.
 4.The circle X^2 + Y^2 + 2x - 4y - 11 = 0 and the line X-y+1=0 intersect at A and B.Find the equation of the circle having AB as diamater.
 
 Thank you in advance!
 Best regards,
 Kalin Mihow
 Answer by Alan3354(69443)
      (Show Source): 
You can put this solution on YOUR website! 1.A circle whose centre lies on the line y=3x-1, touches both axes: find:
 (A) the equation of the circle
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 If by "touches" you mean tangent, then the center has to be on the line y = x to be equidistant from both axes.
 Find the intersection of y=3x-1 and y = x.  Call it (h,k)
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 The radius of the circle is the distance, h.
 The eqn is
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 (B) the points where the circle intersects the line 2y+x=1
 Solve for the 2 points.
 ==============================================
 2.Find the equation of the circle which passes through the points (0,3), (-1,2) and (7,-4)
 Do you know about determinants?
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 3.A circle passes through the points (1,-15) and (-11,3). Its centre lies on the line 5y-12x+22=0. Find the coordinates of the centre, the radius and the equation of the circle.
 Try it, email via the Thank You note for help or to check your work.
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 4.The circle X^2 + Y^2 + 2x - 4y - 11 = 0 and the line X-y+1=0 intersect at A and B.  Find the equation of the circle having AB as diamater.
 Try it, email via the Thank You note for help or to check your work.
 
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