Imaginary FOILED? What is i -1 squared?

Question

(i-1)*(i-1) =

-1 -2i +i

Answer 1

(i-1)(i-1) = -1 -2i + 1 = -2i

(i-1)^2 =-2i

FOIL leads to (i-1)^2 = i^2 -i - i +(-1)^2 = -1-2i+1 = -2i

that also means the square root of -2i = i-1 or 1-i

(1-i)^2 also = 1-2i-1 =-2i