I can't see the whole pic...
what is written on the side?? I can see part of it and I think it is telling you what to do. If not what is thew question?? All you are showing is the lines.
I think the answer is -x+2.
6/10 and 13/20, sorry i would explain this but its late, cheers.
Hope this Helps.
The answer is option 2: 4b = 7. The other options all equal 4.