Explanation for Question 19 From the Math (No Calc) Section on the 2019 March Sat
Question 19 asks if T is greater than zero and three T squared, 2 minus five times three T minus 14 is equal to zero. 3 What is the value of T? So I'm going to start by rewriting this 4 equation, but, uh, I'm going to square three T squared. 5 So that becomes nine T squared minus five times 6 three T is 15 T minus 14 7 is equal to zero. Then I'm going to divide the whole thing by nine. 8 So that gives me T squared minus 15, 9 over nine T minus 14, 10 over nine is equal to zero. 11 And then this middle part can simplify to 12 five over three T minus 14, 13 over nine is equal to zero. 14 So now we have to think what two things multiply together to equal negative 15 14 over nine, and add together to equal negative five over three. 16 And that is negative seven, 17 over three and positive 18 two over three. And 19 so we know that T is equal to seven, 20 over three and T is equal to negative two 21 over three. But the question tells you that T is greater than zero, 22 which means that the answer is the positive value we got or seven.