A circle has the equation x2 + (y + 2)2 = r2. If the circle is shifted 2 units to the left, 5 units up, and the radius is doubled, what will its new equation be? Homework Help ✎
The general equation for a circle is (x − h)2 + (y − k)2 = r 2
where the center is at (h, k) and the radius has length r.
Be sure to square the doubled radius correctly: (2r)2
(x + 2)2 + (y − 3)2 = 4r 2