Answer Choices
i −1 + 12
i −1 − 6
i 15 + 12
i
Explanation for Question 2 From the Math (No Calc) Section on the Official Sat Practice Test 1
So for number two, they've told us that I is equal to the square 2 root of negative one, and we need to find the sum of seven plus 3 three, I plus negative eight plus nine. 4 So let's go ahead and rewrite that. 5 And if I'm trying to add these together, we can notice that I have 6 a plus in front of the parentheses, so I can rewrite this whole thing 7 without any parentheses. And that won't change anything. 8 Let's rewrite that it'll just make it easier for me to work with because 9 now the parentheses are in the way. And the last step here is going 10 to be to combine like terms. So I see a seven, 11 I see a minus eight that would combine to give me negative one. 12 And I see a plus three I and a plus nine. 13 I, and that would combine give me plus 12. 14 I, and so the key here is that we can think of the eye 15 as just a normal variable. For example, 16 if this was an X, instead, we might know that we should combine like 17 terms and add three X plus nine X. So we can think about the 18 eye in the same way. Um, and this, 19 this is useful information. However, we don't actually have to use it because we 20 don't end up with any I squared's. 21 Right. And we know that I squared is negative one, 22 but since we're just combining like terms here, this particular bit of information doesn't 23 actually get used in the math. And so that leads us to the correct 24 answer of a.