Explanation for Question 15 From the Math (Calc) Section on the 2020 March Sat
So here in 15, we have a graph, right? 2 And we have free points in the graph points, 3 a, B and C. And the question asks us for which of the following 4 inequalities, well, each of the points, 5 a, B and C be contained in the solution region. 6 So the first thing we should talk about here is what these inequalities are 7 showing, right? Cause if we look at a, 8 let's say, for example, I replaced the inequality sign right here with an equal 9 sign. It would be, Y is equal to negative X minus two. 10 And this graph would look something like this, 11 right? It would have a wine or step that's negative, and it would also 12 have a negative slope. However, 13 when I replace it with this inequality sign, 14 my graph now becomes not a line, 15 but a region. And you'll notice I'm making the line dashed here. 16 We make the line dash, whenever you have, 17 um, no line underneath when it's not a less than or equal to, 18 but rather just the less than, or just a greater than. 19 Um, but what I have here is Y is greater than that line. 20 So I actually shade above the line. 21 So rather than my solution being a straight line of points is actually a 22 region or a zone of the graph that encompasses multiple different, 23 uh, points, um, and a lot of different places. 24 Right? And so really the best way to go about this question is to 25 look at each of our answer choices, graph them on the graph and then 26 decide when my answer would all three of my points be contained in that 27 regio...