Question

Cho A= \(\frac{-x-3}{x}\)

Tìm x để A < -1

Answer 1

Để A<-1

\(\Leftrightarrow\)\(\frac{-x-3}{x}< -1\)

\(\Leftrightarrow\)\(\frac{-x-3}{x}+1< 0\)

\(\Leftrightarrow\)\(\frac{-x-3+x}{x}< 0\)

\(\Leftrightarrow\frac{-3}{x}< 0\)

\(\Leftrightarrow x>0\)

Vậy x>0 thì A<-1

Answer 2

Để A=\(\frac{-x-3}{x}\)< -1

==> \(\frac{-x-3}{x}\)+1<0

==>\(\frac{-x-3+x}{x}\)<0

==>\(\frac{-3}{x}\)<0

==> x>0