It might be the first one or the second one. i said MIGHT!!
-8.1
Step-by-step explanation:

<em>Times </em><em>all </em><em>by </em><em>9</em><em> </em><em>to </em><em>get </em><em>rid </em><em>of </em><em>fraction</em>
<em>
</em>
<em>Take </em><em>2</em><em>1</em><em>.</em><em>6</em><em> </em><em>away</em><em> </em><em>from</em><em> </em><em>both</em><em> </em><em>sides</em>
<em>
</em>
<em>Divide</em><em> </em><em>by </em><em>-</em><em>4</em>
<em>
</em>
Answer:
=> Apply law of cosine

=> input value

=> simplify

=> calulcation

=> apply rule: Distance must be greater than 0
which is about 14.51828
7/9 = 14/18
14-5=9
9/18=1/2
It would be: 6 4/5 / 3 2/9
= 34/5 / 29/9
You can re-write it as:
= 34/5 * 9/29
= 306/145
In short, Your Answer would be 306/145
Hope this helps!