Question

find the product and write the result in standard form.
7i(-3i + 6)

○ 21 + 42i
○ 42i + 21i²
○ 42i - 21i²
○ -21 + 42i

Explanation:

Step1: Distribute 7i to each term

$7i(-3i + 6) = 7i(-3i) + 7i(6)$

Step2: Calculate each product

$7i(-3i) = -21i^2$, $7i(6) = 42i$

Step3: Substitute $i^2=-1$

$-21i^2 = -21(-1) = 21$

Step4: Combine terms in standard form

$21 + 42i$

Answer:

21 + 42i