# Math

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Determine an equation of the circle that is tangent to both axes, has its center in the fourth quadrant and passes through the point (8, -9).

Thanks much!

• Math -

well, you know if it is tangent to both axis, the center is at r,-r

It passes through 8,-9 so the distance from that point to the center is also r.

r^2=(8-r)^2 + (-9+r)^2
= 64-16r+r^2+81-18r+r^2
r^2-34r-145=0

(r-29)(r-5)=0
r=29, or r=5

then put it in standard form.

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