In order to solve this we need to make on part of both statements equal.
Since 12 is divisible by 6 lets do that.
Multiply everything in the second package by 2.
It then becomes 6 pairs for $12.
So now have have 6 or 8 pairs for $12.
You are getting a different amount for the same price therefore they are not proportional.
Here we are given the equation 3x+k =c
Here in order to solve for x , first let us bring k to the right side.
k is in addition on the left , so when we bring it to the right it gets subtracted

now we have to isolate x on the left side , 3 is in multiplication with x , so when we bring it to the right side we divide by 3
Answer: 