To answer this question, we need to recall that: "the diagonals of a parallelogram bisect each other"
Thus, we can say that:
[tex]DE=EB[/tex]
And since: DE = 3x - 3 , and EB = x + 11, we have tha:
[tex]\begin{gathered} DE=EB \\ \Rightarrow3x-3=x+11 \end{gathered}[/tex]
we now solve the above equation to find x, as follows:
[tex]\begin{gathered} \Rightarrow3x-3=x+11 \\ \Rightarrow3x-x=11+3 \\ \Rightarrow2x=14 \\ \Rightarrow x=\frac{14}{2}=7 \\ \Rightarrow x=7 \end{gathered}[/tex]
Therefore, the correct answer is: option D
