Since supplementary angles are angles that equal to 180, you first need to subtract 40 from 180 to find out what the equation equals. This is the layout of the equation. 140=4x+20. Next you subtract 20 from each side, 120=4x then you divide by 4 four, x=30.
I believe the answer is A) Not possible not sure
The answer would be 30 over 4
