we are given
amount is $1,728.57
so, [tex] A=1728.57 [/tex]
the account is 3.4% compounded daily
so,
[tex] r=0.034 [/tex]
[tex] n=365 [/tex]
If he opened the account nine years ago
so,
[tex] t=9 [/tex]
Let's assume
initial deposit is P
now, we can use formula
[tex] A=P(1+\frac{r}{n})^{n*t} [/tex]
now, we can plug values
[tex] 1728.57=P(1+\frac{0.034}{365})^{365*9} [/tex]
now, we can solve for P
[tex] P\frac{365.034^{3285}}{365^{3285}}=1728.57 [/tex]
[tex] P=\frac{1728.57\cdot \:365^{3285}}{365.034^{3285}} [/tex]
[tex] P=1272.91 [/tex]
so,
initial deposit is $1272.91.........Answer