x^2+6x+5/x^2+8x+15

Question

for what values is # underfined.

Answer 1

I recall responding to a very similar, perhaps the same question yesterday.

Unless you clarify with brackets where the division starts and ends, I cannot be precise in my answer
the way it stands, only the x^2 is divided, so the expression is undefined for x=0

I am certain you meant:
(x^2+6x+5)/(x^2+8x+15) which then
= ((x+1)(x+5))/((x+3)(x+5))

= (x+1)/(x+3)

so the expression is undefined for x = -3, or x=-5

Some would argue that the expression is undefined for x = -3, and indeterminate for x = -5.