Answer:
x=7
Step-by-step explanation:
In order for this figure to be a rhombus, the interior sides have to add up to 180, and the angle not given by an expression has to be 90.
90+8x+7+3x+6=180
Combine like terms
90+11x+13=180
103+11x=180
Subtract 103 from both sides
11x=77
Divide both sides by 11
x=7
