
Patrick B. answered 11/23/19
Math and computer tutor/teacher
the denominator factors as (x+4)(x+3)
therefore the vertical asymptotes are at x=-4 and x=-3, and these values are NOT
in the domain...
So the domain is (-inifinity, -4) U (-4,-3) U (-3,infinity)
for long term behavior, divides everything by x^2, the highest power of x:
4/x - 1/x divided by (1 + 7/x + 12/x^2)
as x goes off to infinity, the function dissipates to zero.
so there is a vertical asymptote at y=0, which the function will cross at x=1/4