Answer: \(y=2\sqrt{2}\,\mathrm{e}^{-x}\sin(\sqrt{2}x)+9x^2-12x+2\).
We solve
\(\displaystyle \frac{\mathrm{d}^2y}{\mathrm{d}x^2}+2\frac{\mathrm{d}y}{\mathrm{d}x}+3y=27x^2\).
First solve the associated homogeneous equation
\(y''+2y'+3y=0\).
The auxiliary equation is
\(m^2+2m+3=0\).
So
\(m=\frac{-2\pm\sqrt{4-12}}{2}=-1\pm i\sqrt{2}\).
Hence the complementary function is
\(y_c=\mathrm{e}^{-x}\big(A\cos(\sqrt{2}x)+B\sin(\sqrt{2}x)\big)\).
For a particular integral, try
\(y_p=px^2+qx+r\).
Then
\(y_p'=2px+q\),
\(y_p''=2p\).
Substituting gives
\(2p+2(2px+q)+3(px^2+qx+r)=27x^2\).
So
\(3px^2+(4p+3q)x+(2p+2q+3r)=27x^2\).
Equating coefficients:
\(3p=27\), \(4p+3q=0\), \(2p+2q+3r=0\).
Hence
\(p=9\), \(q=-12\), \(r=2\).
So the general solution is
\(y=\mathrm{e}^{-x}\big(A\cos(\sqrt{2}x)+B\sin(\sqrt{2}x)\big)+9x^2-12x+2\).
Now use the conditions.
When \(x=0\), \(y=2\):
\(2=A+2\), so \(A=0\).
Differentiate:
\(y'=\mathrm{e}^{-x}\big(-\sqrt{2}A\sin(\sqrt{2}x)+\sqrt{2}B\cos(\sqrt{2}x)\big)-\mathrm{e}^{-x}\big(A\cos(\sqrt{2}x)+B\sin(\sqrt{2}x)\big)+18x-12\).
When \(x=0\), \(y'=-8\):
\(-8=\sqrt{2}B-A-12\).
Since \(A=0\),
\(\sqrt{2}B=4\Rightarrow B=2\sqrt{2}\).
Therefore the required particular solution is
\(y=2\sqrt{2}\,\mathrm{e}^{-x}\sin(\sqrt{2}x)+9x^2-12x+2\).