in wavy curve how to decide whether to from +ve or -ve sign while desciding sign scheme?

WE CAN UNDERSTAND WAVY CURVE METHOD BY THE FOLLOWING EXAMPLE :

     LET THE EQUATION BE   (x-a)(x-b)(x-c)  > 0

                                       (x-e)(x-f)(x-g)

IN THE GIVENN QUESTION WE ARE ASSUMING THAT   a,b,c    ARE LESS THAN ZERO.

FURTHER WE ASSUME THAT        g>f>e>0>c>b>a

       - + -    + -     + -      +   

                   a                b                     c                       0                     e                  f          g

HENCE THE SOLUTION WILL BE 

X BELONGS TO (A,B)U(C,0)U(E,F)U(G,∞)

APPROVE THE ANSWER IF HELPFUL.

THIS IS HOW WE ASSIGN - OR + SIGN WHILE DECIDING THE SIGN SCHEME.