Question 1081520
Problem:

Which of the following should the limit be evaluated using the dividing out technique?

<img src = "https://i.imgur.com/0tmoLTG.png">

--------------------------------------------------------------------------


The answer is choice B. Here's why


If we plug x = 4 into the expression, we run into the problem having 0 in the denominator. Notice how x-4 turns into 4-4 = 0 when we replace x with 4. Luckily, we can factor the numerator to get x^2-16 = (x-4)(x+4). A pair of "(x-4)" terms will cancel leaving just x+4. At this point, we plug in x = 4 to get x+4 = 4+4 = 8 which is the limiting value.