Which of the following products yield a real number? Select all that apply.

Johan Faerch asked Sep 9, 2023

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Johan Faerch asked Sep 9, 2023

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16 votes

Answer:

The choice 4 and 6 ;

7i(7i)

and

(9 + 3i)(9 - 3i)

Explanation:

$7i(7i) = 49 {i}^(2) = - 49$

__o_o__

$(9 + 3i)(9 - 3i) \\ = 81 - 27i + 27i - 9 {i}^(2) \\ = 81 + 9 \\ = 90$

Xcut answered Sep 15, 2023

by Xcut

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