Explanation for Question 5 From the Math (No Calc) Section on the 2017 May Sat
No, let's do question back. So question five, 2 ask us for the value of X and we're essentially going to have to 3 factor here. There's two ways to do this problem. 4 We're going to go over both of them. The first is just to work 5 with what we have with the X minus two, distribute everything, 6 and then factor that way. So let's start with that. 7 That's first. Write it out. We have X minus two times X minus two 8 because of the squared minus six X minus two, 9 plus nine equals zero. For the first part we foil, 10 we get X squared minus two X minus two X 11 plus four. For the second part, 12 we distribute you negative six X plus 12. 13 Don't forget those negative signs. And then plus nine equals 14 zero. Next step is combining like terms. 15 So the X squared that's the only value. 16 Um, so we keep it like that. 17 And then we combine all the Xs. We have the negative two X 18 negative, two X and negative six X, 19 which adds up to a negative tenants. 20 Then we combined the integers. 21 We have the four, the 12 and the nine, 22 which adds up to 25 and that's all equal 23 to zero. So now we can actually factor. 24 We set up our two binomials. We put our Xs in the first times 25 because X times X equals X squared. 26 And we need to find two numbers that multiply to see, 27 which is 25 and add up to beat, 28 which is negative 10. These numbers are negative five and negative 29 five. Now this does all equal to zero or 30 final step and to solve for X, 31 we want to get each of t...