Okie, so percent decrease is the amount loss divided by the original number and multiplied by 100 to find the percent. This is because you are finding the amount loss in terms of the total amount - percent basically.
The amount loss : 4 feet
4 feet/ 12 feet = .3333 (ratio of how much cut) multiply by 100 --> 33.3% decrease. From 12 feet to 8 feet is a 33.3 % decrease. I hope this helps :-)
In dividing two equation with variables and exponent, First you must align or rearrange the equation and group them base on their variables but don't forget the sign of each variables. Second, proceed in dividing its quantity and then subtract its exponent to the other variables having the same. So by calculating it, the answer would be X or X^1
0.05n + 0.25q = 1.60
q = 3n
0.05n + 0.25(3n) = 160
0.05n + 0.75n = 1.60...multiply by 100 to get rid of the decimals
5n + 75n = 160...answer D
