Question

How do you graph `x^2+y^2+8x-8y-93=0`?

Answer 1

You can transfrom it as follows

#x^2+8x+16+y^2-8y+16-93-32=0=>(x+4)^2+(y-4)^2=125=> (x+4)^2+(y-4)^2=(5sqrt5)^2#

which is a circle with centre at `(-4,4)` and radius `r=5sqrt5`

The graph is