Explanation:
You must first add 20 to all inqualies, leaving u with 0 is greater than or equal to 2x which is also greater than or equal to 40.
Divde everything by 2 to get rid of the 2 from the x
0 divided by 2 is 0, 2x divded by 2 is x, 40 divided by 2 is 20.
Thats the answers