Explanation for Question 23 From the Math (Calc) Section on the 2019 May Sat
So question 23 says the graph of the equation. 2 I X plus K Y equals six is a lie. 3 And the X, Y plane, where a and K are constants. 4 If the line contains the points negative two, 5 negative six and zero negative three, 6 what is the value of K? So what this problem wants us to do 7 is plug in these two coordinates to create a system of equations. 8 So let's start by doing that. So the first equation we're going to plug 9 in negative two for ax. So we have negative two, 10 a plus negative six Y because 11 we're plugging in negative sex for Y or sorry, 12 negative six K actually, because we're plugging in negative six for Y. 13 So we fix that negative six K is equal to six. 14 And the second line is zero a. 15 So there is no E there plus negative three K is 16 equal to six. So now that we have these two 17 equations, we can solve for one of the variables and plug that into find 18 the second variable. So let's start by solving for K. 19 So to do that, I'm going to divide both sides of the bottom equation 20 by negative three. And I get K is equal to negative 21 two. And since this equation, 22 or sorry, because this question is only asking for the value of K, 23 we don't actually need to find the value of eight. So the answer is 24 a, or negative two.