Answer:
x =17
Step-by-step explanation:
The angles are supplementary so they add to 180
6x-20 + 6x - 4 = 180
12x -24 = 180
Add 24 to each side
12x-24+24 = 180+24
12x = 204
Divide by 12
12x/12 =204/12
x = 17
