Answer
False
Work Step by Step
Let us consider an example: $\dfrac{d^3y}{dx^3}-2\dfrac{d^2y}{dx^2}-4\dfrac{dy}{dx}+8y=0$
Write auxiliary equation: $r^3-2r^2-4r+8=(r+2)(r-2)^2=0$
$r_1=-2; r_2=2$
So, we have three linearly independent solutions to the equation such as: $y_1=e^{-2x}, y_2(x)=e^{2x}$ and $y_3(x)=xe^{2x}$
Therefore, the given statement is False.