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Solve z² + 1 = 0:

Az = ±1
Bz = -1
Cz = ±i
Dz = 1
Answer & Solution
Correct answer: C. z = ±i
We have z² = -1 → z. So z² = ±i. *Note: complex numbers were invented to give meaning to √(-1) = ±i.*
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