Explanation for Question 9 From the Math (No Calc) Section on the 2018 May Sat
Question number nine asks, which of the following is a solution to the equation 2 above. So since all of the answer choices here have radicals in them 3 that indicates that I'm probably going to have to use the quadratic equation. 4 So I've written that out here, this is the quadratic equation. 5 It's an alternate way to factor. Um, 6 and just so we know what's plugin, I've written down here that a is 7 equal to one. That's the coefficient from here B is equal to negative four, 8 which I got for me here. And C is equal to two, 9 which I got from it here. So let's plug in those values and see 10 what X equals. So the opposite of B is just positive for foster 11 minus root B squared is 16, 12 four times a times. C is just eight and two 13 a is equal to two. This can be simplified into four plus 14 or minus 16 minus eight, which is just eight. 15 So Groot eight, over two, 16 and route eight can become four plus or minus two root 17 two over two. 18 And then finally, I'm going to divide this whole equation by two and I 19 get to plus or minus root two. 20 And the only answer choice here that fits that is two plus root two, 21 or answer C. So that's the correct answer.