[tex]bonjour \\ a = 7x {}^{2} - 2x = x(7x - 2) \\ b = 121 - 36x {}^{2} = \\ \sqrt{121 = 11} \\ \sqrt{36 {x}^{2} } \\ (11 - 6x)(11 + 6x) \\ identite \: remarquable[/tex]
[tex]c = x {}^{2} - 7 \\ (x - \sqrt{7) \: \: \: \: \: \: (x + \sqrt{7)} } \\ identite \: remarquable[/tex]
