CPM Homework Help : INT3 Problem 5-30

A circle has the equation $x^2+(y+2)^2=r^2$ . If the circle is shifted $2$ units to the left, $5$ units up, and the radius is doubled, what will its new equation be?

Hint:

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 $r$ .

More Help:

Be sure to square the doubled radius correctly: $(2r)^2$

Answer:

$(x+2)^2+(y−3)^2=4r^2$