I assume you're trying to show that . To do this, you need to show , in other words, show .

Working on the last inequality, we have

So we need a lower bound for . Remembering that we are letting x get very close to -1, so that the distance between them is small, we can choose a value that will make that distance small (and we're going to make it smaller anyway). It doesn't matter what value we choose, as long as it is sufficiently close. So say we let . That means

Therefore we can say .

So an appropriate is .