Determine whether y varies directly with x. If so, find the cos tang of variation and write the equation.

Answer:
Yes, [tex]k=-\frac{1}{2}[/tex] and [tex]y=-\frac{1}{2}x[/tex]
Step-by-step explanation:
The given line passes through the origin.
It has equation of the form y=kx.
Hence it is a direct variation.
The line passes through(2,-1).
This implies that;
[tex]-1=2k\implies k=-\frac{1}{2}[/tex]
The equation of variation is
[tex]y=-\frac{1}{2}x[/tex]