I don’t understand how to do this i need help fast time test

Answer:
C
Step-by-step explanation:
If AD is 20 then BC is also 20. Another way to solve it too is by AD is 20 and 3x+5 = 20 so do 20-5, which is 15 and 15 divided by 3 is 5 which is the amount X is.
Answer:
I am guessing C.
Step-by-step explanation:
I hope this helps!