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