Answer
True
Work Step by Step
Let us counter an example:
$(D^2-4D+5)^2y=0$
The four linearly independent solutions to equation are: $y_1(x)=e^{2x}cos x $, $y_{2x}=e^{2x}\sin x $, $y_3(x)=e^{2x}x\cos x$ and $y_4(x)=e^{2x} x \sin x$
The general solution is: $y(x)=c_1e^{2x}cos x +c_2e^{2x}sin x+c_3 e^{2x}x\cos x+c_4 e^{2x}\sin x$
Therefore, the given statement is true.