Explanation for Question 13 From the Math (No Calc) Section on the 2020 March Sat
So question number 13 is asking us for the, 2 some of the solutions to the given equation. 3 Right? So what that first means is that we need to find the solutions 4 to the equation. And we also need to know how to do that. 5 If we look at our equation here, we see we have some Xs. 6 So when it says to find the solutions, it wants us to find what 7 the values are of X, right? 8 So solutions are basically X values where this equal sign where 9 X squared minus 14, X plus 40 is actually equal to two X plus 10 one. And we do this by factoring, 11 right? But in order to factor, 12 we need to have our quadratic equation or polynomial set 13 equal to zero. So what that means is I'm going to subtract the two 14 X and the one from this side, 15 so that what I have as a polynomial is actually equal to zero. 16 And then from there I can factor. So the X squared we'll say at 17 squared, negative 14, minus two is negative 16. 18 So I'll have a negative 16 X and then 40 minus one that's 39. 19 So plus 39 is equal to zero. 20 And now I can think about, okay, how do I factor this? 21 Right. So I'll start by putting a double bubble. 22 And I see that my first term is X squared. 23 And I can only make that one way by doing X times X. 24 So I'll have an X at the beginning of each double bubble. 25 And then I want to find numbers that will multiply to get me negative 26 39 and we'll add, 27 so that's a multiply. And then I want them to add, 28 to give me negative 16. Right? So let's think of some...