Slope of a Line Passing through two points (x₁ , y₁) and (x₂ , y₂) is given by :

Given Points are (-3 , 5) and (6 , -1)
here x₁ = -3 and x₂ = 6 and y₁ = 5 and y₂ = -1

Option D is the Answer
To start this problem, we know that one of the three pieces that the string is cut into is 15 meters longer than the others. Subtract 15 from 42 to get 27.
Then, from there, you can cut that number (<em>divide</em>) by three to get the length of the two shorter strings. Simply add the 15 meters you didn't use yet to one of the pieces to find the longer string, and you have your lengths.
Hope this helps!
-refrac532
Well if he is filling one 3/4 quart bottle, then he must fill his measuring cup 3 times, so just multiply it by 5, and you have 15.
David needs to fill the measuring cup 15 times.