Answer: These Lines are <em>Parallel</em>
Step-by-step explanation: For two lines to be parallel, they must have the same slope with different y-intercepts. Both of the lines above have a slope of 3 and differing y-intercepts of 4 and -5. Therefore, these lines must be parallel to one another.
 
        
                    
             
        
        
        
4 = 2*2
6 = 2*3
9 = 3*3
LCD = 2 * 3* 2 * 3 = 36
so the fractions are 3/4 * 9/9 = 27/36 
5/6 = 30/36 and 5/9 = 20/36
 
        
             
        
        
        
X // Y,    Y //  Z,    
By inference  X //  Z
The third option.
        
             
        
        
        
Answer: it is a direct variation.
Justification:
In a direct variation the variables are related by a proportionality constant in this way:
y = k x
Tthan means that the value of y is always the product of a constant times the value of x.
The situation discribed for the coal may be written as:
number of tons of coal burned: c
number of hours: h
⇒ c = k × h
Which is that you can calcualte the number of tons of coal burned at any time, once you know the proportionality constant k.