Answer: The slope of the line is 
Step-by-step explanation:
The slope of a line can be calculated with the following formula:

Then, given the points
and
, you can identify that:

Knowing these values you can substitute them into the formula for calculate the slope:

Finally, evaluating, you get that the slope of that line is:

B. To see if it’s a function, it has to pass the vertical line test. That means draw a vertical line (going up and down) through any point on the graph and it can only go through one point. If it goes through more than 1, it’s not a function. Like in graph A, if you draw a vertical line at x=-2, it will go through two points, same at x=2. For graph b, no matter where you move a vertical line, it only passes through one point at a time, so it passes the vertical line test.
A(t)=A0*(1/2)^(t/30)
where t=elapsed years
A0=initial mass at t=0.
$7200.. you would find out what 3.5% of $6000 (210) is and then multiply it by 6 (1200) and then add it to the original $6000