Hello,
If you lose 3 pounds per week, after 3 weeks you lose (3)(3) = 9 pounds.
The change in your weight is represented by the integer 9 (pounds).
Hope this helps!
You would need to use the distance formula.
Distance = Sqrt((x2-x1)^2+(y2-y1)^2)
Plug in your numbers
Distance = Sqrt((12+4)^2+(12-18)^2)
Distance = 17.09
Unit rate means how much does it cost for 1 unit
2.64 for 12 pencils
find 1 pencil
divide both sides by 12
0.22 for 1 pencil
0.22 per pencil