Given f(x)=2x3−9x2+12x+5,x∈[0,3]
Differentiating w.r.t x,
⇒f′(x)=6x2−18x+12
⇒f′(x)=6(x−1)(x−2)
For maxima/minima f′(x)=0
⇒6(x−1)(x−2)=0⇒x=1,2
Now, f"(x)=12x−18
So at x=1,f"(x)<0
and at x=2,f"(x)>0
So, for absolute maxima/minima
⇒f(1)=10
⇒f(2)=9
⇒f(0)=5
⇒f(3)=14
⇒M=14
⇒m=5
∴M−m=9