a, Ta có: \(\left|x-3\right|\ge0\)
=>\(-5+\left|x-3\right|\ge-5+0\)
=>\(M\ge-5\)
Dấu"=" xảy ra <=>x-3=0=> x=3
Vậy Min M= -7 <=> x=3
b,Ta có :\(-\left|x-3\right|\le0\)
=>\(9-\left|x-3\right|\le9-0\)
=>\(M\le9\)
Dấu "=" xảy ra <=>x-3=0 =>x=3
Vậy Max M= 9 <=>x=3