#feedback for all these invalid example I would like to see them turned into valid examples to better understand the formal arguments

x

A -> B

A -> F

It is stated that a chain cannot be made because 2 sides match. But during Q1 they match these:

Weed -> meth

LSD -> /meth

How does this work? is it because one of them is negated? If so why can't I simply negate the first example to connect them

For number 1, if I said

"without physical exercise, health will deteriorate"

is that correct or not?

I came up with answers like these for most of them but they were not given

Is using the symbols necessary? I feel like I understand it better before and the symbols are just complicating things more?

So the example of Elias is valid but not Kumar. Isn't the Kumar example the contrapositive of the Elias argument tho? How is it not valid