To do this problem, we're going to start by factoring out of two, and we get a ^2 + 2 A -24 left. So we want to figure out two numbers that multiply to give us -24 and add to give us two. So one and 24, two and 12/3 and eight, four and six. So if it was a -4 and a +6, the sum would be two. So if we have two a ^2 -, 4, A plus six a -, 24. Now we can do some factoring by grouping. The first two have an A in common, leaving us a -, 4. The 2nd 2 have a +6 in common, leaving a -, 4. Whenever we do this method, those two parentheses absolutely positively must be the same, or if we've messed up somewhere. So those two terms each had an A -, 4 in common. If I take those out, I get left a + 6.