Angles ABD and DBC are adjacent. Beam BM is the bisector of angle ABD. Find angle ABD

Angles ABD and DBC are adjacent. Beam BM is the bisector of angle ABD. Find angle ABD if ABM angle = DBC angle + 12 degrees

Adjacent angles are two angles with a common vertex, one of the sides of which is common, and the remaining sides lie on one straight line (not coinciding). The sum of adjacent angles is 180 °.
If the BM ray is the bisector of the angle ∠ABD, then ∠ABM = ∠DBM, since the bisector divides the angle in half.
Let’s make the equation:
∠DBC = x;
∠ABM = x + 12;
∠ABD = 2 • ∠ABM = 2 • (x + 12);
∠ABC = ∠ABD + ∠DBC = 180 °;
2 (x + 12) + x = 180;
2x + 24 + x = 180;
2x + x = 180 – 24;
3x = 156;
x = 156/3 = 52 °
∠ABD = 2 (x + 12);
∠ABD = 2 (52 +12) = 2 • 64 = 128 °.
Checking: 128 ° + 52 ° = 180 °.
Answer: ∠ABD = 128 °.