Question

Which is the radius of a circle whose equation is (x + 1)2 + (y - 1)2 = 25?

30
25
5
4

Answer 1

\[(x-a)^2+(y-b)^2=r^2\]

equation of a circle centered at (a,b) with radius r

Answer 2

So 25=r^2 what is r=

Answer 3

Huh? can you write the steps out so i know how to Do it?

Answer 4

\[(x-(-1))^2+(y-1)^2=5^2\]
using what zarkon wrote
what is a=?
what is b?
what is r?