(3,5)....x1 = 3 and y1 = 5
(1,3)....x2 = 1 and y2 = 3
slope formula : (y2 - y1) / (x2 - x1)
slope = (3 - 5) / (1 - 3) = -2/-2 = 1 <== slope is 1
15) Basically, this year Chelsea is making 64 cups of soup, and since there are 16 cups in a gallon, Chelsea will make 4 gallons.
16) Option D
Your answer is in the picture.
The question is a bit ambiguous: you may mean

or

Anyway, in both cases, the domain of a function involving a square root is found by imposing the content of the root to be greateer than or equal to zero. So, in the first case you have

In the second case, you have
