Choose an equation that does not represent a direct variation.Group of answer choicesy = -5xy = 0.9xy = 1y = x

To determine which equation does not represent a direct variation, we first need to recall the definition of direct variation. An equation represents direct variation if it can be expressed in the form $y = kx$, where $k$ is a non-zero constant. Now let's analyze the given options:

1. $y = -5x$: This is a direct variation since it can be expressed in the form $y = kx$ with $k = -5$.

2. $y = 0.9x$: This is also a direct variation as it can be expressed in the same form, with $k = 0.9$.

3. $y = 1$: This equation does not depend on $x$ and is simply a horizontal line. There is no relationship represented by a variable $x$, so it does not fit the form $y = kx$.

4. $y = x$: This represents a direct variation where $k = 1$.

Conclusion

Thus, the equation that does not represent a direct variation is $y = 1$.