 So a useful thing to remember in math and in life is to try the easy things first. So if we want to reduce and simplify this expression, we might begin by noticing that in our numerator, we can remove a common factor of 4. So factoring the numerator gives us... Next, you might notice that z squared minus 49 is a difference of squares. And since z squared minus 49 is a difference of squares, it's easy to factor as... Now if we sit and stare at our factors, we see that these two are almost the same. One of them is 7 minus z, and the other one is z minus 7. Yet almost think they could be related. Well, in fact, they are related. Remember that for any real numbers or variables representing real numbers, a minus b is the same as the additive inverse of b minus a. So we could reverse either 7 minus z or z minus 7, but because we like to have our variables first, let's reverse the subtraction in the numerator, and so we'll get z minus 7 and another negative. So remember, we can only remove a common factor when both numerator and denominator are products. So it's good to check. The numerator is minus 4 times z minus 7. The denominator is z minus 7 times z plus 7. And since they're both products, we can remove the common factor and get our final answer. So rather than trying to type this in and get all of the parentheses located in the correct place, let's go ahead and pull up our math formatting window. Remember that'll appear when we click inside the answer box, then click on this yellow up arrow. We're trying to enter in a fraction, so let's use this fraction bar. We'll type in the numerator, type in the denominator, save enters. The preview shows that what we've entered is what we wanted to enter, and so now we can click on Submit.