What is the equation of a line that contains the points (0, 8) and (8, 8)?

Answer 1

If you don't see that our points are horizontal from each other...

m = (8 - 8)/(0 - 8) = 0/-8 = 0

Well, with a slope of 0, we have a horizontal line, where both points have a y-value of 8, so y = 8.

Don't know that a slope of 0 gives us a horizontal line?

y - 8 = 0(x - 0)

y - 8 = 0

y = 8

orrrr...

8 = 0 + b

b = 8

y = 0x + 8

But, hey, we don't write 0x. That's just 0 and mathematicians are lazy and don't write 0 unless we have to.

y = 8

Answer 2

y = 8

To be rigorous, plug the points into the slope/intercept form:

y = m*x + b

Using 2 points, you get 2 equations that you can solve for m and b.

BUT---notice that y = 8 regardless of what x is.......thus the equation is simply y = 8.