When an angle is bisected it means that the bisector splits the angle in exactly half. This means that m<ABD and m<CBD are equal. Knowing this you can make an equation of setting them equal to each other so that you can solve for x:
![(x)/(2) + 17 = x - 33](https://img.qammunity.org/2020/formulas/mathematics/college/znvwje0q6ctnq2x5tfhovz5g03gdoojyty.png)
First combine like terms:
![(x)/(2) - x = - 33 - 17](https://img.qammunity.org/2020/formulas/mathematics/college/7jpwvcahlkrp5ltuv10ciztfwvydktozp7.png)
![(-1)/(2)x = -50](https://img.qammunity.org/2020/formulas/mathematics/college/2npv43ekllv2ii8y20nx6t53itsrwrnjro.png)
Now isolate x by multiplying -2 to both sides
x = 100
Now to find m<ABC add both m<ABD and m<CBD together while plugging 100 in for x:
![(100)/(2) + 17 + 100 - 33](https://img.qammunity.org/2020/formulas/mathematics/college/qv45ub82qx16wyia6l9kp85m5ls73dmilq.png)
50 + 17 + 100 - 33
134
Hope this helped!
~Just a girl in love with Shawn Mendes