Answer:
20 or D.
Step-by-step explanation:
You simply plug in the values given for a and b:

So, your answer is 20.
The main property is as follow
(A^p)^q=A^pxq
so only Sam's work is correct because
(8^4)^5 x(7^3)^9=(8^4x5)x(7^3x9)=8^20x 7^27
We can use the points in either order and you will still get the same slope. I usually solve in order that is given. So the first coordinates I label (x1,y1) and the second is (x2,y2).
Slope=m=(y2-y1)/(x2-x1)
m=(9-5)/(3-1)=4/2=2
Slope is 2.