Question

Is the line with equation y = -8 horizontal or vertical?

Answer 1

Horizontal.

Explanation:

Think of what you've got here.

You know that the equation of a line in slope-intercept form is

`color(blue)(y = mx + b)`, where

`m` - the sloper of the line;
`b` - the coordinate of the `y`-intercept on the `y`-axis.

Now, the equation for your line looks like this

`y = -8`

Notice that it's missing the `x`-term. This means that the slope of the line must be equal to zero.

What this tells you is that for any value of `x`, the line will intersect the `y`-axis in the exact same place, `-8`.

Therefore, the line described by the equation `y = -8` must be horizontal.

graph{y + 8 = 0.001x [-13.17, 12.15, -11.11, 1.54]}