2. What will be the extension of this spring if the load is a) 4N and b) 75 g?

I think is 75 because is the only one that has a weight letter in the variable

Step-by-step explanation:

So, after 6 months, they both have the same number of coins.  

Step-by-step explanation:

Jack has 56 coins

Jill has 80 coins

Jack collect 12 coins per month

Jill collect 8 coins per month

Let after m months, they both have the same coin.

56 + 12 m = 80 + 8 m

12 m - 8 m = 80  - 56

4 m = 24

m = 6

So, after 6 months, they both have the same number of coins.