Answer:
a. 70°
Step-by-step explanation:
m∠BDC + m∠CDA = m∠BDA
-3x + 34 - 2x + 56 = 150
-5x + 90 = 150
-5x = 60
x = -12
m∠BDC = -3x + 34 = -3(-12) + 34
= 36 + 34 = 70°
