Question

Simplify the expression (9 + 2i)(9 − 2i).

81 − 18i
81 + 18i
77
85

Answer 1

Answer:

=85

Step-by-step explanation:

I'm pretty sure I'm correct

Answer 2

Answer:

85

Step-by-step explanation:

Apply complex arithmetic rule:  (a + bi) (a - bi) = a^2 + b^2  A = 9  B = 2

= 9^2 + 2^2

= 81 + 4

= 85

Therefore, the answer is 85