Question

(2-6i) (2+6i)

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Answer 1

Short answer: 40

Explain:

2 + 6i)(2 - 6i) = 2(2) + 2(-6i) + 6i(2) + 6i(-6i) = 4 -12i + 12i - 36i2 = 4 - 36i2

remember that i is the square root of -1. That means if we square i we get -1 so

4 - 36i2 = 4 - 36(-1) = 4 + 36 = 40

Answer 2

4+12i-12i-36i^2

4-36i^2

If you need to solve further:

By definition, i^2 is −1.

The 12i - 12i cancels out.

So:

4 - 36(-1)

4+36

= 40