Answer:
-2
Step-by-step explanation:
[tex]y = kx + n[/tex]
When you insert the given points you get
[tex]3k + n = 4 \\ [/tex]
[tex]7k + n = - 4 \\ [/tex]
Than you multiply the first one by - 1 and sum it with the second to get rid of n
[tex]4k = - 8 \\ k = - 2[/tex]
