​​Tìm x; y

1. ​​$$\begin{gathered} Tìm x; y biết: \\ /x-1/+/y-2/=0 \end{gathered}$$

.........................................................................................................
           2.       $$\begin{gathered} a) Tìm GTNN: \\ A= /x+2020/+2021 \\ b) Tìm GTNN: \\ B= 2020-/x-1/ \end{gathered}$$