I'm going to assume that they are on parallel tracks, and not the same track.
60x=40(x+2)
60x=40x+80
20x=80
x=4
You can check the work I've provided by filling in the answer for x into the initial question.
ʕ·ᴥ·ʔ
If Im correct I believe the answer is the last one
Answer:

Step-by-step explanation:
Hello,
let s assume that m+n is different from 0
we have this equation and we need to find m as a function of t, s, and n

<=>

for t-s different from 0, so t different from s
hope this helps
The First one (A) because it’s a straight line