Explanation for Question 1 From the Math (No Calc) Section on the 2019 October Sat
Now question number one is asking us, which of the following is a solution 2 to the equation. Two X plus three equals seven. 3 And when they ask, what is the solution? 4 What they're really asking you to do is solve for X. 5 So we can rewrite our equation here, two X plus three equals seven. 6 And if we're going to solve for X, we want to remove everything that 7 is attached to the X in this equation. 8 And that case there's a two attached to the X and there's the plus 9 three. Now first you always want to remove the things that are addition or 10 subtraction from the X, everything about PEMDAS. 11 If you're solving for X, you want to move backwards across PEM dos. 12 So the first thing that we do is addition and subtraction. 13 So we'll subtract three from both sides. 14 That way these threes can cancel and that'll leave us with two X is 15 equal to four. 16 And now what we want to do is multiplication and division. 17 We can see that we have a two X, right, 18 essentially a two times X. 19 So to remove that too, so we can get X on its own. 20 We need to divide by two, four divided by two is two. 21 So that means that X is equal to two. And our correct answer is 22 C if you were unsure of what to do with, 23 um, this math here, but you could do is take an answer and plug 24 it in to this equation also as a way to check your work. 25 Right? So if I do two times two, 26 so I'm replacing the X with the two plus three is equal to seven. 27 I can look at this side of the equation and we know that two 28 times two is four. And if I add three right, 29 four plus three seven, so our equation is true. 30 And again, our best answers going to BC.