Explanation for Question 9 From the Math (No Calc) Section on the 2020 March Sat
So question nine is asking us to find the equation of aligned with the 2 two points that they've given us. Right? And so here, 3 I've written out the two points and I've kind of labeled each part of 4 the points, right? I've labeled this point is 0.1 and this one is two 5 and then labeled the X's and the Y's. And the reason that I've done 6 this is because I saw that all of our answer choices are in slope 7 intercept form, which means that I need to know the slope and I need 8 to know the Y intercept. And now if you're being a savvy test taker, 9 you can notice immediately that all of the slopes are different, 10 right? So if we solve for the slope, we can get our answer choice 11 in half the time. We don't even need to solve for the y-intercept because 12 the slope will immediately tell us, which is correct. 13 So let's go ahead and do that. The equation for slope is Y two 14 minus Y one over X, two minus X one. 15 Now you can see why it was useful for me to label my points 16 here in red, because I can just plug and chug. 17 Right? I said that my Y two is 15 and my Y one was 18 three. My X two is five and my X one was one. 19 And if I subtract those, I get 12 over four or three, 20 right? So I want to pick an answer with a slope of three. 21 And there's only one answer that does that. And it's a, 22 so if you were taking the test, you could do this. You can move 23 on and be done with a, but since we're here to really go over 24 these answer choices and why some are wrong a...