a)2|3x-2|-1
Vì 2|3x-2|\(\ge0\)
Suy ra:2|3x-2|-1\(\ge1\)
Dấu = xảy ra khi 3x-2=0
3x=2
x=\(\frac{2}{3}\)
Vậy Min A=1 khi x=\(\frac{2}{3}\)
b)5|1-4x|-1
Vì 5|1-4x|\(\ge\)0
Suy ra:5|1-4x|-1\(\ge\)-1
Dấu = xảy ra khi 1-4x=0
4x=1
x=\(\frac{1}{4}\)
Vậy Min B=-1 khi x=\(\frac{1}{4}\)