Write the product in standard form.
-$$( 5 + 9 i ) ( 5 - 4 i )$$
A) $- 11 + 65 i$
B) $- 36 i ^ { 2 } + 25 i + 25$
C) $61 + 25 \mathrm { i }$
D) $61 - 25 \mathrm { i }$

Question

Quizplus · Accepted Answer

To multiply two complex numbers, use the distributive property (FOIL method): $(5 + 9i)(5 - 4i) = 25 - 20i + 45i - 36i^2$. Since $i^2 = -1$, the expression simplifies to $25 + 25i + 36 = 61 + 25i$.

Write the Product in Standard Form (5+9i)(5−4i)( 5 + 9 i ) ( 5 - 4 i )(5+9i)(5−4i)

Write the Product in Standard Form $( 5 + 9 i ) ( 5 - 4 i )$