Hi there!
Your question is mistaken. You must have meant to ask for the value of x.
By definition of a parallelogram, we know that there must be two pairs of parallel sides. We also know that a parallelogram will follow this form:
See attachment.
Therefore, we know that
. Let's solve:
![6x-15=x+15](https://img.qammunity.org/2020/formulas/mathematics/middle-school/i6hvyutgsf8d3ho9a2uoc68oqoxa3do221.png)
Subtract x from both sides.
Add 15 to both sides. Now the variable is isolated.
Divide both sides by 5.
So as you can see, x = 6. If you tried to solve this and got a negative solution, remember that lengths and distances can never be negative (e.g. I can't go -5 miles; a square can't have a length of -3 feet, etc.).
Hope this helps! :^)