help me simplify these complex expressions? :) Algebra 2

Question

anonymous · Answer

ANSWER CHOICES: 
7i over 10,
-7i over 10,
-7 over 10,
70i over 100i^2.

anonymous · Answer

$$6\sqrt{3} , -6\sqrt{3} , 6i \sqrt{3} , -6i \sqrt{3}$$

anonymous · Answer

technically, i is a radical since $\large i=\sqrt{-1} $, so to simplifiy $\large \frac{7}{10i} $, you would multiply both numerator and denominator by i....

anonymous · Answer

thankyou, but i'm not quite sure what that would be. 7*sqrt -1 divided by 10i* sqrt -1 ?? @dpaInc

anonymous · Answer

$$\huge \frac{7}{10i} = \frac{7}{10i} \cdot \frac{i}{i}= $$
can you simplify it from here?

anonymous · Answer

ie, simplifying complex numbers is like simplifying radicals....

anonymous · Answer

well, the only thing i know to do here is cross mulitply but you can't do that @dpaInc

anonymous · Answer

cross multiply?  you're multiplying fractions here.... just go straight across....

anonymous · Answer

what the numerator gonna be?
denominator?

anonymous · Answer

14i over 20 i?

anonymous · Answer

how did you get 14i for the  numerator? 7 times i = 7i...

anonymous · Answer

and the denominator:  10i times i = $\large 10i^2 $

anonymous · Answer

oh goodness. :0