If 81=n-3(-5+4n)
81= n+15-12n
81= -11n+15
-11n=81-15
-11n=66
n=-6
as AB || DE then
angle BAE = angle AED
so angle AED = 70
as AD = AE then
angle AED = angle ADE = 70
now in a triangle
angle DAE + Angle ADE + angle AED = 180
angle DAE + 70 + 70 = 180
angle DAE = 180 - 140 = 40
Principle refers to the size of the loan.
So I believe Principle would be the right answer