f(x)=∣2x+1∣−3∣x+2∣+∣x2+x−2∣=∣2x+1∣−3∣x+2∣+∣x+2∣∣x−1∣
=∣2x+1∣+∣x+2∣(∣x−1∣−3)
Critical points are x=2−1,−2,−1
but x=−2 is making a zero twice in product so, points of non differentiability are x=2−1 and x=−1
∴ Number of points of non-differentiability =2