Write the general equation for the circle that passes through the points:
(1, 7)
(8, 6)
(7, -1)
You must include the appropriate sign (+ or -) in your answer.
x^2 + y^2__x__y=0

Question

Write the general equation for the circle that passes through the points:
(1, 7)
(8, 6) 
(7, -1)
You must include the appropriate sign (+ or -) in your answer. 
x^2 + y^2__x__y=0

mathstudent55 · Answer

The equation of a circle with center (x, y)and radius r is

$(x - h)^2 + (y - k)^2 = r^2$

You have three given points.
Substitute one point at a time into the equation above to get 3 three equations in three unknowns, h, k, and r.
Solve the system of equations and substitute the values of h, k and r in the above equation.

anonymous · Answer

Ok so I have to put (1,7) into that equation you gave me??

mathstudent55 · Answer

That is one way of doing it but it's a lot of work unless you have an electronic way of solving the system of equations.

mathstudent55 · Answer

Here is another way of solving.

mathstudent55 · Answer

Here is a circle with two points on it and a chord drawn through them.
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mathstudent55 · Answer

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mathstudent55 · Answer

The perpendicular bisector of the chord passes through the center of the circle.
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