2) John has 100$ dollars in his bank account. when he gets a job, he gers 4200 a day, and he put the money in the bank.
How much money after x days?
How much money after 10 days?

Step 1 ：First, we need to understand the problem. John has $100 in his bank account and he earns $4200 per day from his job which he deposits in his bank account.

Step 2 ：We are asked to find out how much money he will have after x days and after 10 days.

Step 3 ：Let's denote the amount of money John has in his bank account after x days as M(x).

Step 4 ：Since John earns $4200 per day and he starts with $100, we can express M(x) as follows: \( M(x) = 100 + 4200x \)

Step 5 ：This equation tells us that to find out how much money John has after x days, we just need to multiply 4200 by the number of days and add 100.

Step 6 ：Now, let's calculate how much money John will have after 10 days. We substitute x with 10 in the equation: \( M(10) = 100 + 4200*10 \)

Step 7 ：After calculating the above expression, we get: \( M(10) = 100 + 42000 = 42100 \)

Step 8 ：So, John will have $42100 in his bank account after 10 days.

Step 9 ：To check our solution, we can substitute x with 10 in the original equation and see if we get the same result: \( 100 + 4200*10 = 42100 \)

Step 10 ：Since the result is the same, our solution is correct.

Step 11 ：So, the amount of money John has in his bank account after x days is given by the equation \( M(x) = 100 + 4200x \) and after 10 days he will have $42100.