Question

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

Answer 1

Yes,
`k=-(1)/(2)` and
`y=-(1)/(2)x`

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;

`-1=2k\implies k=-(1)/(2)`

The equation of variation is

`y=-(1)/(2)x`