Question

A={x E R\2-x>1},obtinem A=?

Answer 1

$2 - x \ \textgreater \ 1 \Rightarrow -x \ \textgreater \ -1 \Rightarrow x \ \textless \ 1 \Rightarrow x \in (-\infty, 1) \\ \\ \Rightarrow A = (-\infty, 1)$

Answer 2

A={x∈RI2-x>1}
⇒2-x>1
   -x>-2+1
   -x>-1    I×(-1)
⇒x<1    (dupa ce am inmultit cu -1 s-a schimbat semnul)
⇒x∈(-∞, 1)
A=(-∞, 1)