<span>commutative property of addition
answer is
</span><span>A. 12 + 6 + 15 = 12 + 15 + 6</span>
        
                    
             
        
        
        
1.) 3 (3t + s)
distribute 
9t + 3s
plug in the variables
9 ( 12 ) + 3 ( 9 )
108 + 27
135
2.) 2s - t
plug in the variables
2 ( 9 ) - 12
18 - 12
6
I hope this helped and i sincerely hope that this was the brainliest answer!
have a nice day
 
        
             
        
        
        
Answer: C
Step-by-step explanation:
πr^2 is how you find area
r=1/2(d)
r=1/2(12)
r=6
6^2=36
36π
 
        
                    
             
        
        
        
Its pythagoras I think ^^; so 9^2 + 4.5^2 = 101.25 then square root it to get 10.0623059   just in future do a^2 + b^2 = c^2 (adjacent squared plus opposite squared gives you the longest side which is the hypotenuse squared) I hope that helps! ^^; 
        
             
        
        
        
Answer:
x= -8
y= -17
Step-by-step explanation: