Question

Which of the following is equivalent to Square root -63

Answer 1

`3i √(7)`

Explanation:

The imaginary unit is
`i=√(-1)`.

Now 63 itself is not a perfect square but 63 does contain a factor that is.

63=9×7 and 9 is a perfect square.

So
`√(-63)=i √(63)`.

`i √(63)=i √(9 \cdot 7)=i √(9) √(7)=i(3) √(7)=3i √(7)`