Hi Natasha,
Some great questions here! Please see my responses below:
1. I think I know what you're referring to, the solution is advising that you use the right hand CURLED rule to find the direction of the magnetic field that the wire on TOP exerts on the wire on the BOTTOM. Then it uses the right hand rule with your index finger, middle finger and thumb all at 90 degrees to each other to find the force. You use the field you got from the CURLED right hand rule to find the force using the other right hand rule. Now, the reason current is to the left is because they're examining the effect created by the field exerted from the top wire on the bottom wire, in the bottom wire the current is to the left. You would then repeat this process: what is the effect of the field exerted by the bottom wire on the top wire? Since current in the top wire is to the right, you would then align your finger to the right.
2. I think I understand what you mean here. The graph of an inverse relationship looks like a hyperbola. Here's a link:
https://www.google.com/u...4XdgesCFQAAAAAdAAAAABAD
I hope this helps!