Răspuns :
[tex] {x}^{2} - 6x + 9 = {x}^{2} - 3x - 3x + 9[/tex]
[tex] = x(x - 3) - 3(x - 3)[/tex]
[tex] = (x - 3)(x - 3)[/tex]
[tex] = {(x - 3)}^{2} [/tex]
[tex] = x(x - 3) - 3(x - 3)[/tex]
[tex] = (x - 3)(x - 3)[/tex]
[tex] = {(x - 3)}^{2} [/tex]