Explanation for Question 12 From the Math (No Calc) Section on the 2019 April Sat
For number 12, we are given this equation and we are looking 2 for a solution to the equation. 3 So just by looking at the answer choices, 4 I can tell that we are going to have to use the quadratic formula. 5 So if you don't have it memorized, 6 it is negative B plus or minus the square root of B squared 7 minus four, AC all over two way. 8 This formula is very helpful for the sat. 9 So if you don't already have that memorized, I definitely would. 10 Now we can identify are a, B and C, 11 you know, is equal to four. B is equal to six and C is 12 equal to one. So now we can start plugging in. 13 So we have negative B negative six plus or minus 14 the square root of six squared, 15 minus four times four times one. 16 All of that is over two times four. 17 So now starting to simplify a little bit negative six plus or minus 18 the squared of 36 minus four times four is 16 times. 19 One is still just 16. All of that is over eight. 20 And then you know, that 36 minus 16 is 20, 21 and we still have that divided by eight there. 22 So if we look at our answer choices, you can see that it's not 23 matching up with any of them. And that is because this radical here is 24 not in simplest radical form. Um, 25 you always want to pull out as many perfect squares as you can. 26 So if we think about numbers that multiply to 24 27 is a factor of 20 and four is a perfect square. 28 So if we rewrite squared of 20, 29 that is equal to the square root of four times square to five, 30 you are allo...