Answer:
Explanation:
I reformatted the question to clarify the statements. Please check for accuracy. 
Given that D(x) = 2x, select all of the following that are true statements. 
1. D( x) is a direct variation. 
2. D( x) is a function. 
3. D( x) is a rule for the set of points (5, 10), (6, 12) and (-2, -4). 
4. x is the dependent variable. 
5. D(6) = 3
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1. D( x) is a direct variation. YES. D(x) will always be 2 times x.
2. D( x) is a function. YES.  Each calculated D(x) will have a unique point.
3. D( x) is a rule for the set of points (5, 10), (6, 12) and (-2, -4). YES. Each (x,y) shows a value of y that is 2 times x, as per the equation's instructions.
4. x is the dependent variable. YES. y depends on what value is chosen for x.
5. D(6) = 3 NO.  d(6) = 2*(6) or 12