Step-by-step explanation:
You can solve systems of equations using either substitution or elimination.  For these problems, I recommend elimination.  I'll do the first one as an example.
-3x + 16y = 9
-4x + 8y = 12
Multiply the second equation by -2.
8x − 16y = -24
Add to the first equation (notice the y's cancel out).
(-3x + 16y) + (8x − 16y) = 9 − 24
5x = -15
Solve for x.
x = -3
Now you can plug this into either equation to find y.
-3(-3) + 16y = 9
9 + 16y = 9
y = 0
The solution is (-3, 0).
 
        
             
        
        
        
Answer:
(a) x = 
(b) x = 
Step-by-step explanation:
A. sum of angles in a polygon = (n - 2) 180
The polygon given is an irregular pentagon, where n = 5
So that;
sum of angles in a pentagon = (5 - 2) 180
                         = 3 x 180
                         = 
Thus,
x + 90 + 76 + 110 + 136 = 
x + 412 = 
x =  - 412
 - 412
x = 
B. The polygon given is an irregular pentagon, where n = 5.
Let the supplementary angle with angle 38 be represented by y,
y + 38 = 180
y = 180 - 38
   = 
y = 
Let the supplementary angle with x be represented by z, so that;
z + 72 + 120 + 100 + 142 = 
z + 434 = 
z =  - 434
 - 434
   = 
z = 
But, x + z = 
Then;
x +  =
 = 
x =  -
 - 
   = 
x = 
 
        
             
        
        
        
Answer:
a is the answer
Step-by-step explanation:
a is the answer because the way they are being multiplied are consistent, while the others arent.
 
        
                    
             
        
        
        
Answer:
19.8
Step-by-step explanation:
Since 3.3*6 is 19.8.