Ta có: (x - 15)2 \(\ge\)0
=> A = (x - 15)2 - 2017 \(\ge\)-2017
Dấu '=' xảy ra <=> (x - 15)2 = 0 <=> x = 15
Vậy MinA = -2017 tại x = 15
A=\(\left(x-15\right)^2-2017\)
\(\Rightarrow\left(x-15\right)^2\ge2017\)
Vậy MinA=2017\(\Leftrightarrow\)\(\left(x-15\right)^2=0\)
\(\Leftrightarrow\)x-15=0\(\Leftrightarrow\)x=15