Question

Evaluate and write in standard form $(4-2i)(-3+3i)$, where $i^2=-1$.

• A. $6+18i$
• B. $-6+18i$
• C. $12+18i$
• D. $6-18i$

Answer 1

The correct option is B $-6+18i$

Consider $(4-2i)(-3+3i)$

$\Rightarrow (4-2i)(-3+3i)=4(-3)+4\left(3i\right)-2i(-3)-2i\left(3i\right)$

$=-12+12i+6i-6i^2$

$=-12+18i+6$ ..... (as $i^2=-1$)

$=-6+18i$