Remember that an angle bisector divides the angle into two equal parts, this definition allows us to express the following equivalence.
[tex]m\angle ABD=m\angle DBC[/tex]
Let's replace the expressions.
[tex]2x+5=x+7[/tex]
Now, we solve for x.-
[tex]\begin{gathered} 2x-x=7-5 \\ x=2 \end{gathered}[/tex]
We use this value to find angle ABD.
[tex]m\angle ABD=2x+5=2(2)+5=4+5=9[/tex]
Therefore, angle ABD is equal to 9°.
