The total volume of the buffer represents the sum of the volumes of the acetic acid and sodium acetate solutions. I'll use
This will represent your first equation (notice that I've used liters instead of mililiters).
Since you're dealing with a buffer, use the Henderson-Hasselbalch equation to try and find another relationship between
Plug in the values you have for pH and
Now, the concentration of sodium acetate can be written as
The number of moles of sodium acetate can be found by using the initial concentration of
Likewise, the concentration of acetic acid can be written as
The number of moles of acetic acid will equal
Plug these values into equation (2) and you'll get
These values represent the volumes in liters for the sodium acetate and acetic acid solutions you need to mix to get this buffer.
Therefore, the volume of acetic acetic solution you need is
173.9 ml is required.
2 eqns, 2 unknowns.