I can't get my head around these types of questions i know how to prove a limit you use $\displaystyle |f(x) - L| < \epsilon$ but the question is use the (N, ε) method prove $\displaystyle lim_{x \rightarrow \infty} \frac{7n + 3}{8n + 5} = \frac{7}{8}$

I've read though the notes ive taken on this but still dont get it id be really grateful for some pointers