Answer:
[tex] \boxed{[3 \: \: \: - 12 \: \: \: \: \: \: 15 \: \: \: - 21] } [/tex]
Step-by-step explanation:
[tex]3 \times 1 = 3 \\ \\ 3 \times ( - 4) = - 12 \\ \\ 3 \times 5 = 15 \\ \\ 3 \times ( - 7) = - 21 \\ \\ \\ = > 3.[1 \: \: \: - 4 \: \: \: \: \: \: 5 \: \: \: - 7] =[3 \: \: \: - 12 \: \: \: \: \: \: 15 \: \: \: - 21] [/tex]
