Given,
f(x)={\begin{matrix}|4{x}^{2}-8x+5|, & \mathrm{if}8{x}^{2}-6x+1\geq 0 \\ [4{x}^{2}-8x+5], & \mathrm{if}8{x}^{2}-6x+1<0\end{matrix}
={\begin{matrix}4{x}^{2}-8x+5, & \mathrm{if}x\in [-\infty ,\frac{1}{4}]\cup [\frac{1}{2},\infty ) \\ [4{x}^{2}-8x+5] & \mathrm{if}x\in (\frac{1}{4},\frac{1}{2})\end{matrix}
\Rightarrow f(x)={\begin{matrix}4{x}^{2}-8x+5 & \mathrm{if}x\in (-\infty ,\frac{1}{4}]\cup [\frac{1}{2},\infty ) \\ 3 & x\in (\frac{1}{4},\frac{2-\sqrt{2}}{2}) \\ 2 & x\in [\frac{2-\sqrt{2}}{2},\frac{1}{2})\end{matrix}\begin{matrix} \\ \\ \end{matrix}
Now plotting the graph of f(x) we get,

We can see f(x) is not differentiable at 41,x1,21 (wherex1=22−2)