Answer:
a) 7/4 b) 15/2
Step-by-step explanation:
a) Scale Factor = Image / Object
Take the side of Triangle ABC that's BC Why? Because it corresponds with the Image Triangle ADE's DE
= 21/12 = 7/4
b) 7/4 = 10+ x / 10
Cross Multiply 
= 4 ( 10 + x ) = 70
= 40 + 4x = 70
= 4x = 70-40
= 4x = 30 
= 4x/4 = 30/4 
x = 15/2
 
        
             
        
        
        
Answer:
(9 x 7)/3 + 4
Step-by-step explanation:
9 x 7 = 63
63 divided by 3 is 21.
21 + 4 = 25
 
        
                    
             
        
        
        
Answer:
there could be more than one answer... 
Step-by-step explanation:
 
        
                    
             
        
        
        
x = 2a
a = 3 
x = 2 · 3 = 6 ← the end answer
 
        
                    
             
        
        
        
Okay 
1 yes and yes 
2 yes and no 
3 no and yes