The answer is D, because in the step before that it was proved that the triangles were congruent and CPCTC is used after they are proved congruent.
Step-by-step explanation:
Statement | Reason
CB=AB Given
DBC=DBA Given
DB = DB Reflexive Property
/_\ DBC
=~
/_\DBA SAS
Sorry for the formatting the =~ means congruent.
75m + 800 = 95m + 500
Solve that equation
Which should get you m=15
15 is your answer
