\(A=\left|x+19\right|+\left|y-5\right|+2020\)
Ta có : \(\left|x+19\right|\ge0\forall x;\left|y-5\right|\ge0\forall y;2020>0\)
Suy ra : \(\left|x+19\right|+\left|y-5\right|+2020\ge2020\)
Dấu ''='' xảy ra : \(\hept{\begin{cases}x+19=0\\y-5=0\end{cases}\Leftrightarrow\hept{\begin{cases}x=-19\\y=5\end{cases}}}\)
Vậy GTNN A = 2020 <=> x = -19 ; y = 5