Explanation for Question 31 From the Math (Calc) Section on the 2020 March Sat
So onto question number 30, 1 31 asks us for what value of X 2 is the equation above true. And so perhaps one place where you can get 3 tripped up in this question is the wording. 4 It says, makes this equation true. And so in most cases, 5 you've probably never seen that wording before, but basically all they want you to 6 do is solve for X for this equation, 7 right? Because if we take this equation and we simply solve for X, 8 then that value of X will make the equation true. 9 So whenever you see this wording do what comes naturally right. 10 Solve for X. So let's go ahead and write this. 11 Now, if I want to solve for X, the first thing that I need 12 to get to do right, is to get rid of that exponent. 13 And in order to get rid of an exponent to the fourth, 14 I need to square root it kind of, 15 it's not quite a square root instead. 16 I'll take a fourth root because these fours will cancel right now. 17 When I take the fourth root of zero, I'm basically finding a number that 18 I can multiply four times two equals zero, 19 and that's going to be zero, right? So I have X minus three is 20 equal to zero now by taking the fourth root. 21 And that's also something you can do in your calculator. 22 And now it's a solve for X. I just need to add three to 23 both sides. As our answer shows us the X is equal to three. 24 So three is going to be our correct answer.