What is a radius of a circle given by the equation x²-2x+8y-47=0

First, we are going to rewrite it as a parabola equation.
Rewrite.

Divide by 8.

Factor out coefficient.

Then, we are going to convert x into square form.

Convert the whole expression into square form.

Simplify.

Subtract 6 from both sides.

Divide by coefficient.

Rewrite in standard form.


The radius of the circle will be -2. Also, no matter what the sign says, the radius has to always be positive. 
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