x=(-5.15-5.89i).(30/(-5.15-5.89i))

i is the suare root of (-1)
what is x.
please help me , i cant figure it out.
thank you.

whenever you see an i^2, replace it with a -1.

by the looks of this, I don't think you don't have to worry about imaginary numbers.

x=(-5.15-5.89i).(30/(-5.15-5.89i))

the numerator will cancel with the denominator!