Answer:
x = 17
Step-by-step explanation:
For the parallelogram to be a rhombus then then the diagonal must bisect the given angle, thus
3x - 11 = x + 23 ( subtract x from both sides )
2x - 11 = 23 ( add 1 to both sides )
2x = 34 ( divide both sides by 2 )
x = 17