[tex] {(x - 6)}^{2} - 9 {x}^{2} = {(x - 6)}^{2} - {(3x)}^{2} [/tex]
[tex] = (x - 6 - 3x)(x - 6 + 3x)[/tex]
[tex] = ( - 2x - 6)(4x - 6)[/tex]
[tex] = 2( - x - 3) \times 2(2x - 3)[/tex]
[tex] = 4( - x - 3)(2x - 3)[/tex]
Formulă :
[tex] {a}^{2} - {b}^{2} = (a - b)(a + b)[/tex]
[tex]a = x - 6[/tex]
[tex]b = 3x[/tex]