[Video] Q11: Which of the following numbers is not a solution of the inequality x x 3x − 5 ≥ 4x − 3 ?

Explanation for Question 11 From the Math (Calc) Section on the Official Sat Practice Test 1

So for question number 11 were asked, which of the following is not. 2 So we want to pay attention to we're choosing the one. That's not a 3 solution to this inequality right here. 4 And so usually we think about these having an equal sign in between, 5 right? We'd like to solve things with equal signs, but here we have an 6 inequality symbol. And so it's actually going to give us a range of numbers 7 that could be solutions. And we want to choose a number that is not 8 within that range. So we can start by rewriting the equation. 9 And even though we have this different symbol and any quality symbol, 10 we can still solve the equation. Like there's an equal sign there. 11 So we want to get all of our normal numbers to one side and 12 all of our variables, right. To the other side. 13 So I'll start by adding five to both sides. 14 So that way all my normal numbers are on the right of the equation. 15 So those five fives cancel, I'll be left with three X is greater than 16 or equal to four X plus two. 17 Now I need to get all my exes to the left, right? 18 So I'll subtract four X that'll give me negative. 19 X is greater than or equal to two, not a solve for X. 20 We need to divide by negative one. Right? 21 And so this was one of the most important rules when you're solving any 22 qualities. One of the most easy to forget is that when you divide by 23 a negative, you actually need to flip your sign. 24 So rather than just rewriting the sign as is, 25 we're going to flip the direction. So negative X used to be greater than 26 now. It's a less than or equal to negative two. 27 So all of our possible solutions are negative two and anything less. 28 Right. But we don't want to choose those. 29 Negative two is within our solution range. 30 Negative three is less than negative two and negative five is less than negative 31 two negative one is the only thing that's not within that range. 32 So a has to be our correct answer. 33 Okay.