Answer: OPTION D
Step-by-step explanation:
Based on the figure, we can say that:
[tex]m\angle ABC+m\angle ABD=m\angle CBD[/tex]
Therefore, we can substitute values and solve for "x".
Then, we get that the value of "x" is:
[tex]85\°+\frac{1}{2}x+30 =140\°\\\\115\°+\frac{1}{2}x=140\°\\\\\frac{1}{2}x=140\°-115\°\\\\x=2*25\\\\x=50[/tex]
