Simplify -2i*2i

$- 2 i \cdot 2 i$

Multiply $- 2 i (2 i)$ .

Multiply $2$ by $- 2$ .

$- 4 i i$

Raise $i$ to the power of $1$ .

$- 4 (i^{1} i)$

Raise $i$ to the power of $1$ .

$- 4 (i^{1} i^{1})$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$- 4 i^{1 + 1}$

Add $1$ and $1$ .

$- 4 i^{2}$

Rewrite $i^{2}$ as $- 1$ .

$- 4 \cdot - 1$

Multiply $- 4$ by $- 1$ .

$4$