Question

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

Answer 1

Answer:

81 - 4i^2

Step-by-step explanation:

(9 + 2i)(9 - 2i)

Multiply First number in First parentheses to the first number in the second set of parentheses.

Multiply first number in the first parentheses with the second number in the second parentheses.

So you'll have:

81 - 18i

Then multiply the second number from the first parentheses by the first number in the second parentheses.

And multiply the second number in first parentheses by the second number in the second parentheses.

So then you'll have:

81 - 18i + 18i - 4i^2

Combine like terms:

81 - 4i^2

Final answer is:

81 - 4i^2

Answer 2

Answer:

(9 + 2i)(9 − 2i) = 81 - 4i²

Step-by-step explanation:

a² - b² = (a + b)(a - b)