Algebra
posted by Katy .
I need help! The question is what numbers for which the rational expression is underfined in 8/9x+7

If you meant it the way you typed it there is no restriction.
if you mean 8/(9x) + 7 , then x≠0
if you meant 8/(9x+7) , then x ≠ 7/9
see how important correct placement of brackets is ?