Explanation for Question 24 From the Math (Calc) Section on the 2018 May Sat
Question 24 says in the equation above a, 2 B and C are constants. If the equation is true for all values of 3 X, what is the value of a plus B plus C? 4 So I'm just going to start by distributing the left side of the equation. 5 X times X becomes X squared plus X plus two X 6 plus two, and that's equal to a X squared plus BX 7 plus C. Then I can add and subtract like terms, 8 which are these two middle terms to get X squared plus three 9 X plus two is equal to X squared plus 10 BX plus C. Now this tells us that a is 11 equal to one because that's the coefficient for X squared. 12 That B is equal to three, 13 the coefficient for X. And that C is equal to two 14 because that's the value of the constant. So now let's define what a plus 15 B policy is. I just add these together three plus two is five plus 16 one is six. So that's our correct answer. 17 And the answer is a.