For this case we have to:
Let "w" be the variable that represents the number of savings weeks.
We have that Landon's initial amount is $ 70.
We want to know how much money you have after 5 weeks, knowing that you save $ 7 each week, so be "y" the amount of money after "W" weeks:
[tex]y = 70 + 7w[/tex]
After 5 weeks:
[tex]y = 70 + 7 (5)\\y = 70 + 35\\y = 105\[/tex]
Answer[tex]y = 70 + 7w\\y = 105[/tex]