Answer:

Step-by-step explanation:
Since this is a 30-60-90 triangle, we know that the sides have the following characteristic:
The side opposite to 30 degree angle: n
The side opposite to 60 degree angle: 
The side opposite to 90 degree angle: 2n
Since we know that 7 is opposite to 30-degree, and x is opposite to 60 degree, than we know that x = 
Answer:
Poorly formated. Please fix the question so it is more understandable!
The first option,
both have to be negative, because they were originally both part of the one fraction, which was all negative.
51/3+-39/18
= 89/6
Answer is 14.833333