P = 2W +2L
step is keep 2L in one side of equation , and move every thing else to the other side.
In moving any quantity from one side to other, change the sign. (
equivalent of adding or subtracting equal
quantity from both sides of equation).
2L = P - 2W
divide both sides by 2:
L = p/2 - w
Step is the same as solving X in equation of 8 = 2X + 16
2X = 8 -16 = 8
X =4 . But, here you solve one variable in terms of other variables.
