# Algebra/trigonometry

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• Algebra/trigonometry -

Just expand it
(3-7i)^2
= (3-7i)(3-7i)
= 9 - 42i + 49i^2 , but i^2 = -1
= 9 - 42i - 49
= -40 - 42i

• Algebra/trigonometry -

okay thank you

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