Explanation for Question 14 From the Math (Calc) Section on the 2019 May Sat
So question 14 asks which of the following graphs in the X, 2 Y plane, could it be used to solve the system of equations? 3 So it gives us four different graphs with different lines on it. 4 So it's basically asking which graph accurately depicts these 5 two equations as lines. So to figure this out, 6 I'm going to take both lines and I'm going to put them into the 7 Y equals MX plus B four. 8 So let's start by doing that. 9 So I'm going to subtract X. 10 So I have five Y sequella negative X plus five, 11 and then divide both sides by five. And I get Y is equal negative 12 one, fifth X plus one. 13 So what I know from this information is that the slope 14 of one of the lines is negative one fifth, 15 and the Y intercept is going to be one. 16 And I know that because this is Y equals MX plus B form, 17 where N is the slope and B is 18 the Y intercept. 19 So let's find which of these has that line. 20 So all of them have a line that passes through that 21 passes through the Y intercept. 22 So here, here, 23 here, except for D so we can eliminate D. 24 Now that line also has to have a negative slope, 25 which means that a is incorrect because in a, 26 that line has a positive slope. 27 So because of that, we can cross out any, 28 so this line has a positive slope. Now we can just see which of 29 those two lines has a slope of negative one fifth. 30 This line has a slope of negative one, 31 so we can eliminate B. And just to make sure that this is 32 correct, you can see that thi...