Explanation for Question 3 From the Math (No Calc) Section on the Official Sat Practice Test 6
Question three reads, what is the sum of the complex numbers? 2 Two plus three I and four plus eight. 3 I, or I is equal to the square root of negative one. 4 All right. So we're trying to find the sum. So we want to add 5 this and this. 6 So let's write that out. We've got two plus three, 7 I plus four plus eight. 8 I, and none of the parentheses here are just for visualization. 9 Um, we don't have to actually isolate these two or keep them isolated from 10 each other. So looking at the sum of that, 11 we know that you can add complex numbers and that you can obviously add, 12 um, into as well. So let's group it and we've got two plus four 13 plus three, I plus eight, 14 I, and then simplifying through two plus four is six and 15 3i. Plus eight. I is equal to 11. 16 I that's how we're going to get C as our answer for this one. 17 One thing to note here is, is that we don't actually have to plug 18 in what I is equal to. That's a little misleading. 19 That's in the question. Um, maybe meant to kind of trick you up and 20 the key to know that we don't actually have to plug in the square 21 root of negative one is that we still have an I in our answer 22 choices. So it's totally fine to leave the eye in and leave it in 23 this form as your answer.