Answer:
In the equation, it divides 21 by x before knowing what x is, and gets it incorrect. Instead, you need to divide 21 by -4.2.
Step-by-step explanation:
-4.2x = 21
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     -4.2
    
x = -5
 
        
             
        
        
        
Answer:
x = 90°
3x = 270°
Step-by-step explanation:
Split the shape in half through the plane of 3x and x.
We can find the angle of x/2 is 45°.
Since x/2 = 45°, then we can fid that x=90°.
To find 3x, we simply multiply 90° 3 times.
So 3x = 270°.
 
        
             
        
        
        
Answer:
x = y
Step-by-step explanation:
x/3 + x/6 = 7/2 
2x + x = 21
3x = 21 
(divide 3 on both sides)
x = 7