simplify: (2 - 4i)(3 - 6i)\na -18 - 24i\nb 6 - 24i\nc 6 - 12i\nd -18 - 12i

Explanation:

Step1: Use FOIL method

$(2 - 4i)(3 - 6i)=2\times3-2\times6i-4i\times3 + (-4i)\times(-6i)$

Step2: Calculate each term

$2\times3 = 6$, $2\times6i=12i$, $4i\times3 = 12i$, $(-4i)\times(-6i)=24i^{2}$ Since $i^{2}=-1$, then $24i^{2}=- 24$.

Step3: Combine like - terms

$6-12i - 12i-24=6-24-(12i + 12i)=-18-24i$

Answer:

A. $-18 - 24i$