Explanation for Question 15 From the Math (No Calc) Section on the 2018 April Sat
Question 15 asks, which of the following is an equivalent form of the expression. 2 Two X minus two squared, minus two X minus two. 3 So I'm going to start by just rewriting this as two X minus two 4 times two X minus two, 5 minus R plus negative two X plus two. 6 And immediately we can eliminate answer choice C because these are the same 7 expressions, except our original expression also has negative two X 8 plus two. And this, uh, 9 answer choice C never subtracts two acts and adds two. 10 So it can't be correct. Now we can factor out two X minus two 11 times two X minus two. So that becomes four X squared plus 12 negative eight X plus four, 13 and then plus negative two X plus two after that. 14 And if we add in subtract like terms, it becomes four X squared plus 15 negative 10 X plus six. 16 And from here, just by process of elimination, 17 we come, we can eliminate a and B because it doesn't match either of 18 those answers. But just to show that it actually is answer choice D I'm 19 going to factor this out. So two X times two X is four squared 20 plus negative two or negative two times two X is negative four 21 X plus negative six X plus six. 22 And this becomes four X squared plus negative 10 X plus six, 23 which matches our original expression. 24 So we know that answer choice D is the correct answer.