Bonjour,
[tex]j = ( x- 4) {}^{2} - (2x - 1) {}^{2} [/tex]
[tex]a = x - 4 \: \: \: \: \: \: et \: \: \: \: \: b = 2x - 1[/tex]
[tex] {a}^{2} - b {}^{2} = (a + b)(a - b)[/tex]
Donc :
[tex]j = (x - 4 + 2x - 1)(x - 4 - 2x + 1)[/tex]
[tex]j = ( 3x - 5)( - x - 3)[/tex]
[tex]k = (7x + 8) {}^{2} - (9 - 5x) {}^{2} [/tex]
[tex]k = (7x + 8 + 9 - 5x)(7x + 8 - 9 + 5x)[/tex]
[tex]k = (2x + 17)(12x - 1)[/tex]
