Look up "Everything You Need To Know About Math In One Big Fat Notebook pdf." It's the best thing I've ever been given, I have it with me in math class all the time and I've aced every test.
 
        
             
        
        
        
Answer:
1. 2(k + 3)
2. 3. 75 + k
Step-by-step explanation:
1. 2x + 6
Since, 2 is a common factor of 2 and 6, we can take that common outside.
So, 2x + 6 = 2(x + 3)
Note that in the initial expression, this 2 was distributed to arrive at 2x + 6.
2. (1.5 + k) + 2.25
This is simple addition. We can simply remove the brackets to have: 
1.5 + k + 2.25
Since, the like terms can be added, we will have:
1.5 + 2. 25 + k
= 3. 75 + k
 
        
             
        
        
        
Based from the graph, I think the answer is D. a piece-wise function with separate pieces of linear and step-functions. This is because as you can see from the graph, for intervals [0,1], [5,6], and [10,11] the function is linear. On the other hand, for the remaining intervals, it has a constant value which can be described as a step function. 
        
             
        
        
        
Answer:
B. The average quantity of detergent put into a box by a filling machine greater than one pound
Step-by-step explanation:
The null hypothesis (H0) tries to show that no significant variation exists between variables or that a single variable is no different than its mean While an alternative Hypothesis (Ha) attempt to prove that a new theory is true rather than the old one. That a variable is significantly different from the mean. From the case above option B "The average quantity of detergent put into a box by a filling machine greater than one pound" tries to establish a difference between the variable ("quantity of detergent put into a box by a filling machine") is different from its average/mean