Question

Answer 1

\(a,M=9-\left|x-4\right|\\ \left|x-4\right|\ge0\forall x\\ =>9-\left|x-4\right|\le9\forall x\)

Dấu = xảy ra khi 

\(x=4\)

Vậy \(Max_M=9\) khi \(x=4\)

\(b,N=-\left|x+5\right|-\dfrac{1}{2}\\ \left|x+5\right|\ge0\forall x\\ =>-\left|x+5\right|\le0\forall x\\ =>-\left|x+5\right|-\dfrac{1}{2}\le-\dfrac{1}{2}\forall x\)

Dấu = xảy ra khi

\(x=-5\)

 Vậy \(Max_N=-\dfrac{1}{2}\) khi \(x=-5\)

Answer 2