Résoudre dans \(\mathbf{R}\):
a. \(\frac{1}{x}\)\(\)=-3 S =
\(S=-\frac{1}{3}\)
b.\(\frac{1}{x}\)\(\)≥2 S =
\(S=]0 ;\frac{1}{2}]\)
c.\(\frac{1}{x}\)\(\)≤1 S =
\(S=]-\infty ;0[\cup[1 ;+\infty[\)