how do i solve this using imaginary numbers? PLEASE HELP

Answer:
14 -2i
Step-by-step explanation:
9 + sqrt(-4) - ( -5 + sqrt(-16))
We know the sqrt of a negative number is i * sqrt(number)
9 + isqrt(4) - ( -5 + isqrt(16))
9 + 2i - (-5 + 4i)
Distribute the negative sign
9+2i +5 -4i
Combine like terms
14 -2i