posted by Sissy .
Finding the slope and y-intercept for x = -9, I beleive is (-9, 0) and the slope is undefined.
However what if you are looking for the slope and y-intercept of y = x?
Hmmm. It is a vertical line, so you are right, slope is undefined.
Now y=x is easy
Rewrite it as
y= 1*x + 0
slope is 1, y intercept is zero.