Question

Which of the following is equivalent to Square root -63

Answer 1

Answer:

$3i \sqrt{7}$

Step-by-step explanation:

The imaginary unit is $i=\sqrt{-1}$.

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 $\sqrt{-63}=i \sqrt{63}$.

$i \sqrt{63}=i \sqrt{9 \cdot 7}=i \sqrt{9} \sqrt{7}=i(3) \sqrt{7}=3i \sqrt{7}$