Bonjour,
1)
[tex](3x - 10) {}^{2} - 81[/tex]
[tex] = 3 {x}^{2} - 60x + 100 - 81[/tex]
[tex] = 3 {x}^{2} - 60x + 19[/tex]
2)
[tex](3x + 10 - 9)(3x + 10 + 9)[/tex]
[tex](3x + 1)(3x + 19)[/tex]
3)
(3x -10)(3x +8) = 0
Donc,
3x -10 = 0 => 3x = 10 => x = 10/3
ou
3x +8 = 0 => 3x = -8 => x = -8/3
4)
[tex](3 \times( - 5 )- 10) {}^{2} - 81[/tex]
[tex] = ( - 15 - 10) {}^{2} - 81[/tex]
[tex] = - 25 {}^{2} - 81[/tex]
[tex] = 625 - 81[/tex]
[tex] = 544[/tex]
