Anyone want to help me with this? I will mark brainliest and thanks

Answer:
x = -8
m∠BDC = 68°
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
Equality Properties
Geometry
Step-by-step explanation:
Step 1: Set up Equation
m∠BDC + m∠CDA = 180°
(-7x + 12)° + (-8x + 48)° = 180°
Step 2: Solve for x
Step 3: Find m∠BDC