It B 
x= -12
hope that helps
        
                    
             
        
        
        
Hello from MrBillDoesMath!
Answer:
The first choice ( -12, 20)
Discussion:
Using matrix multiplication we find the equations:
 1x  + 1y = 8                     (A)
 2x  + 3y = 36                   (B)
Next, compute 
   2(A) - B  =>
          (2x + 2y) - (2x + 3y) = 2*8 - 36    =>
           (2x - 2x) + ( 2y-3y) = 16 - 36 =>
           -y = -20  =>
           y = 20
Substituting this y value in (A) gives
          x + 20 = 8 =>
          x = 8 - 20 =>
          x = -12
The answer is the first choice ( -12, 20)
Thank you,
MrB
 
        
             
        
        
        
Answer:
4 1/2
Step-by-step explanation:
Just do the math work it out on paper and check it!
 
        
                    
             
        
        
        
Answer:
36 sq. cm
Step-by-step explanation:
triangle area= 0.5 * 12* 10
rectangle are= 8* 3
60 - 24 = 36
 
        
             
        
        
        
Answer:
c. Mutation 
Step-by-step explanation:
 should be right I hope lol. good luck :)