It is the opposite. There is nothing called same operation...
The answer is 3 and you get that by using the formula for the area of rectangle, p=2L+2W
44=2(4+5w) + 2w
44=8+10w + 2w
44=8+12w
44-8=8+12w-8
36=12w
36/12=12w/12
3=w
If you plug 3 back into the original formula then you see that it is equal to the perimeter of 44
P=2(4+5w) + 2w
P=2(4+5•3) + 2(3)
P=2(19) +6
P=38+6
P=44
1/2 = 3/6
5 gallons of water changed it to 5/6, so that would mean 2/6 would be 5 gallons worth.
5 x 3 = 15.
Hope this helps.
By the binomial theorem,

Each term containing a factor 6 is divisible by 3, since 3 divides 6. The remaining 1 and 2 sum to 3, which is also divisible by 3.