Given, f(x)={\begin{matrix}{x}^{3}-{x}^{2}+10x-7, & x\leq 1 \\ -2x+{\mathrm{log}}_{2}({b}^{2}-4), & x>1\end{matrix}
Now f(1)=3
For x<1,f′(x)=3x2−2x+10>0
⇒f(x) is increasing
For x>1,f′(x)<0
⇒ function is decreasing.
So, at x=1 there is a point of maxima
So, x→1+limf(x)=−2+log2(b2−4)
For maximum value at x=1
⇒3≥−2+log2(b2−4)
⇒32≥b2−4>0
⇒b∈[−6,−2)∪(2,6]