If 16 gallons of water evaporates per week and we have 24 weeks, we can jsut multiply it.
So

gallons of water evaporates.
Since this is in point-slope form, you know one of the points, which is (1,7), and you know the slope, which is -3. So you can plot (1,7) on the graph and then use the slope to plot more points by going down 3 and right 1, or up 3 and left 1.
I have attached my work and the rules of exponents
Answer:
the answer is the second option