Explanation for Question 17 From the Math (No Calc) Section on the 2020 March Sat
Now, if we look at number 17, we can see this asking us what 2 is the value of Y right? And we're giving two equations each with two 3 variables. So what that means is we're going to have to use systems of 4 equations here to either use substitution or elimination to solve for the variable. 5 Y we can see that here, 6 this, uh, equation is really close to being solved for X to take 7 this equation and solve it directly for X. 8 All I have to do is divide by two, right? I have two X 9 is equal to five. If I divide by two and I now know that 10 X is equal to five over two. 11 And so what I can do is I can take this value of X, 12 plug it in here, and then from there solve for Y. 13 So I'm going to rewrite this topic equation, 14 but instead of writing X, I will write five over two, 15 and then continue on. Plus Y is equal to five. 16 So to solve for Y all I have to do is subtract five over 17 two, right? 18 And so you can think about this as also being 10 over two minus 19 five, over two, or you can know that five over two is two and 20 a half, but basically the bottom line is that whichever way 21 you go, you're going to get five over two again, 22 or two and a half. So Y and X are the same thing. 23 They're both going to be five halves.