I tried to solve the follwing limit of function by delta and epsilon but I got stuck with finding the right "N" that for each $x<N$, $|f(x) - L|< \epsilon$, and the hard part was how to get x out of the absolute value, because $x$ is negative. can someone give a clear explanation of this point? and how do I complete this proof?
$\lim \limits_{x \to -\infty} \frac{9x-7x^2}{4x^2+8} = \frac{-7}{4}$