Solution

Assuming we're working with ideal gases
We have:
$V_1=2L=2\cdot 10^{-3} m^3$
$P_1=0.8MPa=0.8 \cdot 10^6 Pa$
$V_2=10L=10 \cdot 10^{-3} m^3$
for an isothermic process, the work done is
$W=nRT\ln(\frac{V_2}{V_1})$
but $P_1V_1=nRT$ , then
$W=P_1V_1\ln(\frac{V_2}{V_1})$
and calculating we get
$W \approx 2575J$