Write the standard form of the equation of the circle that is tangent to x=-2 and has its center at(2,-4).
The form of a circle is (x-h)^2 + (y-k)^2 = r^2, where (h, k) is the center.
If it is tangent to x=-2, and its center is at (2, -4), then its radius is 2-(-2)=4.
Therefore, (x-2)^2+(y+4)^2=16