plz help?!?!?!?!?!?!?!?!?!?!?!?!?!

Answer:
n=5.25 or 21/4
Step-by-step explanation:
Since each side of the triangle is the same, due to it being equalaterial, we know that you can equal two sides to get what x equals.
n=3/4
Input that into any equal, I chose 7n for it's simplicity, and got 21/4, which could also be written as 5.25.