Equation from Three Points*HELP*
posted by Adrianna on .
Write the standard equation for the circle that passes through the points:
(0, 0)
(6, 0)
(0,  8)
You must include the appropriate sign (+ or ) in your answer. Do not use spaces in your answer.
x 2 + y 2 x y = 0
HELP PLEASE I NEED STEP BY STEP EXPLANATION!!
I KNOW THAT THE FORMULA IS =
x^2+y^+dxey+f=0
I JUST DON'T GET IT AND NEED SERIOUS EXPLANATION.

Use this standard circle equation:
(xa)^2 + (yb)^2 = c^2
Your three points tell you that:
a^2 + b^2 = c^2
(6a)^2 + b^2 = c^2
a^2 + (b+8)^2 = c^2
The first two of these equations combine to give:
6a = +or a . Only + sign works.
a = 3
The first and third equations combine to give
b + 8 = +or b
Only  sign works.
b = 4
c^2 = a^2 + b^2 = 25
c = +or 5
So the equation that fits them all is
(x3)^2 + (y+4)^2 = 25