What is (1 +i)5?

Treat the 5 as an exponent. First, (1 + i)² = 1 + 2i + i² = 2i, since i² = −1. Then (1 + i)⁴ = (2i)² = −4, so (1 + i)⁵ = −4(1 + i) = −4 − 4i. The correct choice is −4 − 4i.

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