\(Cho\) \(P=\frac{-1}{2}.\frac{5}{9}.x.\frac{-7}{13}.\frac{-3}{5}\)

\(So\) \(sánh\) \(giá\) \(trị\) \(của\) \(x\) \(với\) \(0\) \(biết\) \(:\)

\(a)P< 0\)

\(b)P>0\)

\(c)P=0\)

\(Tìm\) \(x\)

\(7^{x+2}+2.7^{x-1}=345\)

\(Vẽ\) \(\Delta ABC\) \(.Vẽ\) \(Ax\) \(là\) \(tia\) \(đối\) \(của\) \(AB\)\(.Vẽ\) \(tia\) \(Az\) \(là\) \(phân\) \(giác\) \(của\) \(\widehat{xAC}\) \(.Biết\) \(rằng\) \(\widehat{xAz}=\widehat{B}\) \(.So\) \(sánh\) \(\widehat{B}và\widehat{C}\)

\(Tìm\) \(x,\) \(biết\) \(:\)

\(a)\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}+=\frac{x+1}{13}+\frac{x+1}{14}\\ b)\frac{x+4}{2000}+\frac{x+3}{2001}=\frac{x+2}{2002}+\frac{x+1}{2003}\)