Answer
True
Work Step by Step
Let us counter an example:
$(D+3)^2(D^2+25)^2y=0$
The four linearly independent solutions to equation are: $y_1(x)=e^{-3x}$, $y_12x)=xe^{-3x}$, $y_3(x)=\cos 5x$ and $y_4(x)=\sin 5x$
The general solution is: $y(x)=c_1e^{-3x}+c_2xe^{-3x}+c_3 \cos 5x+c_4 \sin 5x$
Therefore, the given statement is True.