Explanation for Question 29 From the Math (Calc) Section on the 2020 March Sat
So now, as we look at question number 29, 2 we see that it says that in a given equation, which we can see 3 up here, K is a constant. 4 If the equation has no solution, 5 so no solution to this equation, what is the value of K? 6 And so a good way to do this equation or this question is going 7 to be, to plug in each value of K and see if you would 8 be able to get a solution. Right? 9 So first let's try negative one. We have one over three X minus K 10 is equal to K X. And if we plug in negative one for K, 11 it'd be one over three X minus negative one is equal 12 to negative X isn't. 13 Now we can foil this out or rather distribute it, 14 um, to simplify a little bit. So you would get one third X plus 15 one is equal to negative X and now, 16 so let's keep going. 17 Let's see if I can solve it. I could add X to both sides, 18 right? I would end up getting four over three X and that's subtract. 19 Get minus one. So we can see that this is something I could solve. 20 I can now multiply by three, over four to cancel things out. 21 You don't have to solve it all the way, but we can see that 22 when I put in a K as being negative one, 23 I still have an equation that I can solve for an answer choice there. 24 So that means the AI can't be our answer cause we want no solution. 25 So now let's try negative. One-third I have one-third X minus 26 negative one third that's plus one third. And so what I just 27 did there, I kind of did the distributing at the same time is equal 28 to...