Resposta:
Olá,
[tex]a) \: ( - 7) \times ( - 9) \times ( + 13) = [/tex]
[tex]63 \times ( + 13) = 819[/tex]
[tex]b) \: ( + 18) \times ( + 2) \times ( + 3) \times ( - 2) = [/tex]
[tex]36 \times ( + 3) \times ( - 2) = [/tex]
[tex]108 \times ( - 2) = - 216[/tex]
[tex]c) \: ( - 4) \times ( + 2) \times ( - 12) = [/tex]
[tex] - 8 \times ( - 12) = 96[/tex]
[tex]d) \: ( + 4) \times ( - 7) \times ( + 9) \times ( - 13) = [/tex]
[tex] - 28 \times ( + 9) \times ( - 13) = [/tex]
[tex] - 252 \times ( - 13) = 3276[/tex]
