Answer
$12+9i$
Work Step by Step
Use the FOIL method to multiply the binomials.
$3i(4-2i-2i+i^2)$
Substitute $-1$ for $i^2$. Also, add/subtract like terms.
$3i(4-4i+(-1))$
Simplify.
$3i(3-4i)$
Distribute through the parenthesis.
$9i-12i^2$
Substitute $-1$ for $i^2$ And simplify.
$12+9i$