T=21+4.5X
21 is the original temp.
4.5 is the constant rate I got when I subtracted 75-21=54 then divided 54/12min=4.5.
75 =21 + 4.5(12)
See attachment for one such shell. The volume is given by the sum of infinitely many thin shells like this, each with radius

and height determined by the vertical distance between the upper blue curve and the lower orange curve for any given

, i.e.

.
The volume is then
42n, you can't take the "n" away. The "n" means times a number, so I I write n=2, then the expression will be 42 x 2, substitute the n with a 2
You need to distribute the 4 to both the n and the positive 5 so you’re answer would be 4n + 20.
Answer:
Length of Sofa: 6ft / Height of scale model: 15in
Step-by-step explanation:
Sofa:
1 inch = 1 foot
6 inches * 1 foot = 6 feet
Scale Model:
60 feet to a 4 inch scale
60 feet / 4 inches = 15 inches (aka 60 feet)