show that 2i is not a cube root of -8

Question

Question

math algebra

Answer 1

Answer #1

we know that i² = -1,

lets assume cube root of -8 is 2i

which implies, (2i)³ = -8

2³ X i³ = -8

implies 8 X i² X i = -8

we know, i² = -1

-8i = -8 which is NOT true.

Our initial assumption is WRONG . so, 2i is not a cube root of -8.

Answer 2

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