Option D:
k = –2
Solution:
Let y = f(x).
Direct variation:
A relationship between two variables in which one is a constant multiple of the other.
y varies constantly means that y = kx.
The constant [tex]k=\frac{y}{x}[/tex].
Substitute x = –1 and y = 2 from the table.
[tex]$k=\frac{2}{-1}=-2[/tex]
Substitute x = 2 and y = –4 from the table.
[tex]$k=\frac{-4}{2}=-2[/tex]
Substitute x = 5 and y = –10 from the table.
[tex]$k=\frac{-10}{5}=-2[/tex]
Therefore k = –2.
Option D is the correct answer.
