Question

Is the line for the equation y = -8 horizontal or vertical? What is the slope of this

Answer 1

Horizontal and it's slope is 0.

Explanation:

y=a number is horizontal while x=a number is vertical.

The slope of horizontal lines are 0 because there is no rise.

The slope of vertical lines are undefined because there run is 0.

Slope is equal to rise over run.

y=-8 is horizontal because it represents all the points in the form (x,-8) where x is any real number.

Graph as many points as you want in the form (x,-8), you should see a horizontal line formed. The slope of y=-8 is 0.

Example of points in the form of (x,-8):

(-10,-8)

(-5,-8)

(-1,-8)

(0,-8)

(1,-8)

(5,-8)

(10,-8)

All of these go down 8 units after going left or right however many.

This is a horizontal line 8 units below the x-axis.

Answer 2

Horizontal

0

Explanation:

No matter what the x value is, the y value is - 8. Make a small table to see what that means.

x y

2 -8

0 -8

- 2 -8

See what's happening?

Look at the y intercept. The y value is - 8 when x = 0. It is also - 8 when x = 2.

Make a rough drawing on a scrap piece of paper. Plot just those 2 points. Roughly. You don't even need a ruler.

What do you see? The line must be going horizontally.

The next question is a little harder. It is not obvious, but you do know that this line either goes horizontally or vertically. So the slope can either be 0 or undefined. There is no third choice.

The general equation is y = mx + b

There is no x in y = - 8

Therefore the slope is 0. That's the only way you could get rid of the x.