Question

which expression is equal to -2i(4 - i)?
2 - 8i
-8 - 2i
-2 - 8i
8 - 2i

Explanation:

Step1: Apply distributive property

$-2i(4 - i)=-2i\times4-2i\times(-i)$
$=-8i + 2i^{2}$

Step2: Recall $i^{2}=-1$

Since $i^{2}=-1$, then $-8i + 2i^{2}=-8i+2\times(-1)$
$=-2 - 8i$

Answer:

$-2 - 8i$ (corresponding to the third option in the multiple - choice list)