4t 125 Chinczyk How To Do Linear Equations...?

How to do linear equations...? - 4t 125 chinczyk

I know how to do this, the system of equations with two or three variables. For example:
3M-4t = 10
1.2 10 t = 9.8

Everything you need to do is clearly to make the kind of management and M & T, but I do not understand this kind of equation and what makes them different from the one thing I've done.

Example: Liam and Heidi both have $ 125 in the bank. Liam wins $ 15 a week babysitting her mother all her earnings over $ 5 per week for your account. Heidi earn $ 10 per week, but you give your mother 12 weeks for your account. Liam and Heidi both check their balance at the end of each week.

a) How many weeks from the time he had $ 125 balance liams reporting the number of weeks after the $ 125
b) Write and equation liams balance in the number of weeks for about $ 125th

Then the same questinos Heidi?

I do not understand how I set up that may find many of the equation derived eeasier ... someone please tell me, thanx