i squared square root -80

It would be clearer if you had written √ using the sqrt() notation, since the range of the square root would be clear.

I have to guess that the question is:
i squared square root -80
=i² * *radic;(-80)
(=i^2 * sqrt(-80))
=(-1) * sqrt(-2^4 * 5)
=(-1) * 2²sqrt(-5)
=-4sqrt(5)i