Free GRE Prep Hour: Inequalities and Absolute Value

[@mayare1919]

@42:00 if you solve by substituting negative x and positive x (2 possible scenarios with absolute values), one of your simplified answers (as the instructor realized when scribbling), is x squared is less than or equal to negative 4 (and the other solution is x squared is greater than or equal to 2). The GRE doesn't recognize the former equation though (the x squared is less than or equal to negative 4 one) b.c x squared can never be negative on the GRE. As a result, shouldnt the answer be D?

[@mariamazeez7089]

Same thought i had!

[@kumarneupane6699]

@Manhattan Prep GRE, I feel the same, Plz reply !!

[@abhishekchavan1991]

​@@kumarneupane6699I am probably replying very late but the only answer to that is if we take any +ve value of X, then the first equation fails so we have no other option than taking X negative.

[@kumarneupane6699]

I got reply today and I confused about what my original query was 😂. It’s been 2 years and I’m already doing PhD in US (2nd year) lol 😂😂

[@abhishekchavan1991]

@@kumarneupane6699 sorry man, came across this video today! I have my GRE on the 11th of this month. So was revising a few important concepts!

[@laurenemanzi2228]

Hi Cat! @20:00 , I feel like the answer is D, what if a is positive and c is positive?

[@aderoju6966]

This is nice answers how to know which is equal to which

[@dennisoseitutu1037]

Feeling sleepy tonight. I'll come back to watch

[@hammedtukur]

But cant we have ac as -a and -c which will give a positive.

[@adityarana6732]

yes, even i was like why she is not considering both negatives.

[@mohammadabushaera1587]

Thanks for the helpful video, please accept my comment on the way you explained ab>0, bc

[@samrat6546]

good analogy

[@Dana.38]

In 40:35, are you sure that the answer is B and not D? She laterally said we know nothing about y and then chose B..... I am confused.....

[@manhattanprepgre7390]

The right answer to the original question is (D). However, at that point in the lesson, Cat altered the problem so that it said "y is a positive integer," not just an integer. In that case, the givens would tell you something about y, and the answer would change to (B).

[@roroh9818]

@@manhattanprepgre7390 Thank you for your reply. It will be awesome if instructor can highlight the answer to 'original' question. I too was confused as to what the correct answer is for the original question.

[@updownftw]

Thankyou for the video

[@maryem8263]

Chrissy knows it all

[@swarajkumardas2988]

In QC questions are the statements interlinked or independent cuz in the 2nd QC question, there is a probability of a and c being positive. Which makes the answer D

[@manhattanprepgre7390]

The statements are interlinked! So whatever a variable represents in one statement, it has to represent the same thing in the other statement.

[@roumanfirdous8707]

@@manhattanprepgre7390 even if u plug in numers it will still show D as answer, we dont even know if AB, so D is correct answer... try plugging in numbers still gives different answers so D

[@hopefullnes4557]

I got them all right!!

[@angryprogrammer7788]

Can you please recommend any sources for practice of these particular question types?

[@hopefullnes4557]

@@angryprogrammer7788 manhattan series for maths. They are perfect for developing a good understanding

[@rishabhpagaria5367]

@45:00 the answers is wrong it shouldn't be option B it should be D The math was a little wrong as we know x is -ve -X|X| >= 4 putting the -ve value -X(-)|-X| >= 4 X * X >= 4 (because |-X| = X) X^2 >= 4 X >= 2 and X

[@rishabhpagaria5367]

Correction : option B is the correct answer because we know x should be negative so X

[@ntamauwe5786]

i think that b must be greater than zero is correct

[@roumanfirdous8707]

the answer to 2nd question is D not B please correct it

[@chakshutyagi2066]

Ma'am, there is 2 type of books of manhattan 5lb, one in green color cover and second in black cover. which one is better. And what to know before taking a book. please tell me.

[@manhattanprepgre7390]

Hi there! You can see the most current edition of the book here: www.manhattanprep.com/gre/store/gre-strategy-guides/5-pound-book-gre-practice-problems

[@vipultyagi873]

@45:19 how we can take the square root of a negative integer, it is not possible. Even if we take, we will get iota (I) with the integer 2 which is not in the syllabus of GRE. Please clarify if I am wrong.

[@manhattanprepgre7390]

Hi! We checked with Cat on this and here's what she had to say: "Hi! So I think the way I notated/explained this wasn't as clear as it could be. You're correct that we can't take the square root of a negative integer. Here, though, because I'm working with absolute value, I'm using the squared notation just to think about what x could be in the upfront information (and in that case, x can equal a negative, since we aren't squaring x, but rather multiplying x by the absolute value of x, and then by negative 1.) Apologies that the way I explain that in the video led to confusion!"

[@hannahheintz800]

For the problem around 42 minutes - once you establish that x is negative, why do you need to go on to solve the inequality? Won't you know that x is less than 2 by knowing that x is negative??

[@manhattanprepgre7390]

Yes, that's totally true! Cat just wanted to solve it out all the way to demonstrate how the math worked. :)

[@danieladegboyega2254]

Great

[@giljav]

for the first problem, I chose a = -1 and b = -1 and the result gave me a positive number. I don't get why it could no be D or A on the second problem, I solved inequalities as follows: 3x - 21 ≥ 9 +21 +21 3x≥30 /3 /3 x ≥ 10 0.25y - 3 ≤ 1 +3 +3 0.25y ≤ 4 /0.25 /0.25 y ≤ 1 Why is this is this 0.25y ≤ 4 multiplied by 4?

[@ylimes]

For the equation 0.25y - 3 ≤ 1, your calculation is correct up until the end. 4/0.25= 16. So y ≤ 16

[@natarajanparameswaran6752]

4/.25 or 4/(25/100) or (4*100)/25 =16

[@surajpatel1377]

you are so cute, here. 🥰

[@zahirulislam2030]

Meticulous lecture . Wearing glass you seem to be changed !

[@doubleosevenstat7111]

You're really good and very pretty.