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 = 