16:06 Hello, @GreNinja. It's great work you're doing here, very helpful. I'm just a bit confused by question 3. When we evaluate option D, f(-×) gives us -x(x²-2),I understand that. Doesn't multiplying the whole expression by a negative ( to get -f(-x)), give us x(-x²+2), which is not what we started with (x(x²-2)). Please explain further, thank you. And the same question for option E,thanks.
If we consider -x(x^2 -2), this is the same as saying (-1)x(x^2 - 2). If we multiply the whole expression by (-1), we could write this as (-1)(-1)x(x^2 - 2). The two (-1)s would multiply to give (1), so we could write the new expression as (1)x(x^2 - 2) which would simplify to x(x^2 - 2). In order to get x(-x^2 + 2), we would need to multiply our expression by another -1 to change the sign of everything inside that set of parentheses. However, we're only multiplying f(-x) by one -1 to give us -f(-x) so we won't get to x(-x^2 + 2). I'd make the same argument for (E) as I have for (D). I hope that helps, but please let me know if you have any further questions!
for the last question, i just inserted all the options in (3p) and the value of that into f(x), this way i got the correct answers, but hey, using quadratic equation is good too!
Thank you very much. However, I don’t know how did you end up with -7 and 2, since 2-7= -5. Even if 7*-2= -14, there is still the a+b condition to fill for the quadratic equation. Isn’t it? I hope you see and answer my question please 🙏.
@@smilykena9144 hey, haha time goes fast! now i am not preparing for gre and as for your question, lemme check that, i wrote it in one of my books if i find it
@@smilykena9144 i found the answer! so the thing is, i did not use quadratic equation, rather i just substituted all the answer choices into '3p' then the following result into f(x)=x^2-x. Since x=3p here, so i got the correct answer choices which were a and c.
good video, i got 3 out of 7 answers correct, but i learned a lot
16:06 Hello, @GreNinja. It's great work you're doing here, very helpful. I'm just a bit confused by question 3. When we evaluate option D, f(-×) gives us -x(x²-2),I understand that. Doesn't multiplying the whole expression by a negative ( to get -f(-x)), give us x(-x²+2), which is not what we started with (x(x²-2)). Please explain further, thank you.
And the same question for option E,thanks.
If we consider -x(x^2 -2), this is the same as saying (-1)x(x^2 - 2). If we multiply the whole expression by (-1), we could write this as (-1)(-1)x(x^2 - 2). The two (-1)s would multiply to give (1), so we could write the new expression as (1)x(x^2 - 2) which would simplify to x(x^2 - 2).
In order to get x(-x^2 + 2), we would need to multiply our expression by another -1 to change the sign of everything inside that set of parentheses. However, we're only multiplying f(-x) by one -1 to give us -f(-x) so we won't get to x(-x^2 + 2).
I'd make the same argument for (E) as I have for (D). I hope that helps, but please let me know if you have any further questions!
Thank you for the clarification.@@GRENinjaTutoring
@@GRENinjaTutoring Thank you!
All GRE NINJA videos have very good teaching strategies. Thank you GRE NINJA. Happy to come across your channel
thanks dude, you are an awesome teacher
This is more than helpful thank you sir
Can you kindly explain the quadratics in the final question please.
for the last question, i just inserted all the options in (3p) and the value of that into f(x), this way i got the correct answers, but hey, using quadratic equation is good too!
Thank you very much. However, I don’t know how did you end up with -7 and 2, since 2-7= -5. Even if 7*-2= -14, there is still the a+b condition to fill for the quadratic equation. Isn’t it?
I hope you see and answer my question please 🙏.
@@smilykena9144 hey, haha time goes fast! now i am not preparing for gre and as for your question, lemme check that, i wrote it in one of my books if i find it
@@smilykena9144 i found the answer! so the thing is, i did not use quadratic equation, rather i just substituted all the answer choices into '3p' then the following result into f(x)=x^2-x. Since x=3p here, so i got the correct answer choices which were a and c.
if a problem has must in it
only get shoose the anwer you can be sure about from the elements u have
Yes