Perform the desired operation. Write the answer in the form a + bi.
-$- 3 i ( - 4 + 9 i )$
A) $27 + 12 \mathrm { i }$
B) $12 i - 27 i ^ { 2 }$
C) $- 27 + 12 \mathrm { i }$
D) $12 i + 27 i ^ { 2 }$

Question

Quizplus · Accepted Answer

Multiplying $-3i$ by $-4 + 9i$ gives $12i + 27i^2$. Since $i^2 = -1$, this simplifies to $12i + 27(-1)$, which is $12i - 27$, or $27 + 12i$.

Perform the Desired Operation −3i(−4+9i)- 3 i ( - 4 + 9 i )−3i(−4+9i)

Perform the Desired Operation $- 3 i ( - 4 + 9 i )$