a) the equation for a circle is:
[tex](x-h)^2+(y-k)^2=r^2[/tex]
being, r = radius and the center (h,k)
so we have
h=-1
k=2
r= 4
if we replace on the equation, we get:
[tex](x+1)^2+(y-2)^2=4^2[/tex]
and that's the answer to a)
you can write it like
[tex](x+1)^2+(y-2)^2=16[/tex]
b) now, to graph, you need to, go to the center point (x=-1 and y=2) and make a circle from there with radius 4
