Given:
initial deposit = 45
total deposit = 105
w = weekly deposit
x = no. of weeks = 5 weeks
y = amount in dollars
45 + 5w = 105
45 + 5w = 105
5w = 105 - 45
5w = 60
w = 60/5
w = $12 weekly deposit.
y = $45 + $12x
x = (y - 45)/12
To check:
y = 45 + 12(5)
y = 45 + 60
y = 105 total deposit in 5 weeks
x = (105-45)/12
x = 60/12
x = 5 weeks