Evaluate (-4+-i)

i get to
16+4i-4i-i^2

but i'm a little confused,

I get 16-i^2... So you basically distribute everything.
So first, you'd do -4(-4-i) which gets you 16+4i
Next, you do i(-4-i) which gets you -4i-i^2
When you add like terms, (-4i+4i), you're left with 16-i^2. 
So 16-i^2 would be your answer. 

X^2 - 4x +(4/2^2) + y^2 + 8y + (8/2^2) = -4 + (4/2^2) + (8/2^2)(x + 2)^2 + (y + 4)^2 = -4 + 4 + 16your center is (-2, -4) and the radius is the sqrt of -4 + 4 + 16 which is 4