Question

question 4 of 40
simplify the following expression:
$3i(4 - i) + i(6 + 2i)$

a. $13 + i$
b. $1 + 18i$
c. $1 - 13i$
d. $18 - i$

Explanation:

Step1: Expand the first term

$3i(4 - i) = 12i - 3i^2 = 12i - 3(-1) = 3 + 12i$ (since $i^2=-1$)

Step2: Expand the second term

$i(6 + 2i) = 6i + 2i^2 = 6i + 2(-1) = -2 + 6i$

Step3: Add the two results

$(3 + 12i) + (-2 + 6i) = (3-2) + (12i+6i) = 1 + 18i$

Answer:

B. 1 + 18i