Question

sendo f(x) = x+2 e g(x)= -x+1, a soma dos valores inteiros de x tais que f(x) . g(x) > 0 é

a) -2 b) -3 c) 0 d)3 e)2

Answer 1

$\mathrm{f(x)=x+2\ \ \|\ \ g(x)=1-x}\\ \mathrm{f(x).g(x)\ \textgreater \ 0\ \to\ (x+2)(1-x)\ \textgreater \ 0}\\\\ \mathrm{\mathbf{i)}\ x+2\ \textgreater \ 0\ \to\ x\ \textgreater \ -2}\\ \mathrm{\mathbf{ii)}\ 1-x\ \textgreater \ 0\ \to\ 1\ \textgreater \ x\ \to\ x\ \textless \ 1}\\\\ \textrm{Solu\c{c}\~ao}\ \to\ \mathbf{\boxed{\mathbf{-2\ \textless \ x\ \textless \ 1}}}\\\\ \textrm{Soma das solu\c{c}\~oes inteiras}\ \to\ \mathrm{-1+0=\boxed{\mathbf{-1}}}$