2a = b
c = b - 5
d = c - 3
e = d - 1 = a
a = d - 1
a = b / 2
d = c - 3
b = c + 5
d - 1 = b / 2
( c - 3 ) - 1 = ( c + 5 ) / 2
c - 4 = ( c + 5 ) / 2
2 × ( c - 4 ) = c + 5
2c - 8 = c + 5
2c - c = 5 + 8
c = 13
d = c - 3 = 13 - 3 = 10
e = d - 1 = 10 - 1 = 9
b = c + 5 = 13 + 5 = 18
a = b / 2 = 18 : 2 = 9
a = 9
b = 18
c = 13
d = 10
e = 9