Multiply the conjugates.
-$$( 5 - 2 i ) ( 5 + 2 i )$$
A) $25 + 4 \mathrm { i }$
B) 29
C) 21
D) $25 - 4 \mathrm { i }$

Name: Multiply the conjugates. -\[( 5 - 2 i ) ( 5 + 2 i )\] A) $25 + 4 \mathrm { i }$ B) 29 C) 21 D) $25 - 4 \mathrm { i }$
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Question

Quizplus · Accepted Answer

When multiplying conjugates of the form $a + bi$ and $a - bi$, the result is $a^2 - (bi)^2$. Here, $a = 5$ and $b = 2$, so the multiplication yields $5^2 - (2i)^2 = 25 - 4(-1) = 25 + 4 = 29$.

Multiply the Conjugates (5−2i)(5+2i)( 5 - 2 i ) ( 5 + 2 i )(5−2i)(5+2i)

Multiply the Conjugates $( 5 - 2 i ) ( 5 + 2 i )$