Please solve correctly and I will mark brainliest

The angles ABM and MBC sum to the measure of angle ABC. Let's create an equation to model the problem.
ABM + MBC = ABC
Let's plug our values into the variables.
ABM + 150 = 171
Let's solve for ABM. Subtract 150 from both sides.
ABM = 21
Answer:
∠ ABM = 21°
Step-by-step explanation:
∠ ABM + ∠ MBC = ∠ ABC , that is
∠ ABM + 150° = 171° ( subtract 150° from both sides )
∠ ABM = 21°