Answer: 
Step-by-step explanation:
You need to use the following formula:

Given the points A(6,3) and B(8,1), you can identify that:

Now, you can substitute these values into the formula
.
Therefore, you get this result:


Answer:
I think it's the top left one
Step-by-step explanation:
The answer is x= -6/7<span><span></span></span>
1.50x + 450 = 3x
450 = 3x - 1.50x
450 = 1.50x
450/1.50 = x
300 = x
300 copies must be sold to break even
Answer:
D, 30%
Step-by-step explanation:
you move the decimal point twice to the right