S/A= 4.5, D/A=4.5,N/E=.80, A= D+E. SOLVE FOR N/S

is the answer 1

The first two equations tell you that S = D

Two other equations tell you that
D = 4.5A
A = 4.5A + E
-3.5A = E

N/S = N/D = N/(4.5A)= 0.80E/4.5A
= (4/5)(-7/2)A/[(9/2)A]
= (4/5)(-7/9) = -28/45

It looks like the N/S is not 1.