$\begin{aligned}
& 4 x^4+8 x^3-17 x^2-12 x+9 \
& =4\left(x-x_1\right)\left(x-x_2\right)\left(x-x_3\right)\left(x-x_4\right)
\end{aligned}$
Put x=2i&−2i $\begin{aligned}
& 64-64 i+68-24 i+9=\left(2 i-x_1\right)\left(2 i-x_2\right)\left(2 i-x_3\right) \
& \left(2 i-x_4\right) \
& =141-88 i ....(1)\
& 64+64 i+68+24 i+9=4\left(-2 i-x_1\right)\left(-2 i-x_2\right)(-2 i \
& \left.-x_3\right)\left(-2 i-x_4\right) \
& =141+88 i....(2)
\end{aligned}\begin{aligned}
& \frac{125}{16} \mathrm{m}=\frac{141^2+88^2}{16} \
& \mathrm{m}=221
\end{aligned}$