Explanation for Question 3 From the Math (No Calc) Section on the 2017 May Sat
Let's take a look at question three. We are given two equations and we 2 are asked to find the value of Y. 3 So the easiest way to solve this is through system of equations through substitution. 4 Um, and to do that, the first step that we need to do is 5 isolate one variable in one of the equations. 6 So it's going to be easier for us to start with this equation. 7 The first thing we want to do is isolate or solve for X to 8 do that. We multiply both sides by two, 9 and we just get X equals six. 10 So now that we know what X equals, 11 we can really easily solve for Y what we have to do is plug 12 in or substitute the X value in the top equation to 13 do that. We get three, six plus Y 14 equals 12. Now, 15 since we have one equation with one variable, 16 we can just solve for Y first step is, 17 um, to distribute. So we get 18, 18 three times six, and then three Y three times Y equals 19 12, and then to solve for Y with some chucks 18 from both sides. 20 Remember, this is not the calculator section. So you can't use the calculator here. 21 And we got three Y equals negative six. 22 Finally, we divided both sides by three. 23 Then we get Y equals negative two. 24 We make sure that we do want, why not X, 25 sometimes it's easy to mess that up. So make sure you're solving for the 26 right, um, variable. So we get B negative two.