Hello,

0<x+40<180

-40<x<140

~~~~~~~~

0<2x+20<180

-10<x<80

~~~~~~~~

Code:**+*****+*********+*******+*** *-40*****-10********80******140

The intercept of the two intervals is clearly [-10;80]

Plus, we don't want the line to be parallel. So we want ABC and BCD to be different. So we mustn't have x+40=2x+20, that is to say x=20.

Hence -10<x<80, with x different from 20.