Answer: B 
Hope this helps!!
        
             
        
        
        
Step-by-step explanation:
area = ( base 1 + base 2 ) ÷ 2 x height
50 = ( 10 + 15) ÷2 x height
50 ÷ 12.5 = height
height = 4
 
        
             
        
        
        
Answer:
B. Distributive Property
Step-by-step explanation:
You are distributing the 2 to the x and 3.
Hopefully this helped!
Brainliest please?