dux3000

Wonderful! Thanks!

If f(x) = x^2 + 5x + k and f(2) = 6, then f(4) = 12 26 28 36 38 The solution (here http://www.greenlighttestprep.com/module/gre-algebra-and-equation-solving/video/1013 ) finds the value of k and then figures out f(4). I didn't do that. Here's what I did. 2^2 = 4 and 4^2 = 16. 16-4 = 12, so I know that f(4) will be 12 more than f(2) Also, 5(2) = 10 and 5(4) = 20. 20 - 10 = 10, so I know that f(4) will be 10 more than f(2) In both functions we're adding k both times, so there's no difference there. So 12 + 10 = 22, so f(4) will be a total of 22 more than f(2) f(2) = 6, so f(4) = 6+22 = 28 (answer c) Is this a valid solution or did it only work because the numbers worked out nicely?

Hi Rich, How do you know quantity A is ALWAYS bigger?

I know about that strategy but I worry that I don't test the right numbers. Thanks though.

I'm using the Greenlight course and I love it. My math skills are absolutely disgustingly bad but the videos are really helpful. Plus they're all free.

Funny. I came across that same practice question a few minutes after I posted my question. Thanks though!

Actually I did use the adding/subtracting method, but I changed the equations to 6x + 4y = 10 and 6x + 9y = 24 and then I subtracted them to get -5y = -14 I never thought about subtracting them before two of the terms were the same,

3x + 2y = 5 2x + 3y = 8 Quantity A: x Quantity B: y Solution: http://www.greenlighttestprep.com/module/gre-algebra-and-equation-solving/video/972 I solved this by solving for x and y, which turns out to be the slow way. The solution is a lot faster but I don't think I'd ever come up with it on the test. Does anyone have any similar questions that test the same concept so I can practice?

Thanks again TakeruK. I was hoping there was a quick trick to avoid all of that work. Wishful thinking!

Thanks TakeruK! Shoot. I should know that already.I think I've made that exact same mistake before. More coffee!!!!

k < 0 Quantity A: (2k - 5)(k - 1)/(k^2 - k) Quantity B: 2 Worse yet, they say this is a medium question? Is it? Here's their solution http://www.greenlighttestprep.com/module/gre-algebra-and-equation-solving/video/962 Is there an easier way? I never would have gotten this.

The question is: We're told that x does not equal zero. Quantity A: (1+x)/x Quantity B: (1-x)/x I thought the answer would be D because I multiplied both sides by x to be comparing 1+x and 1-x, and either one of those can be bigger. I understand the solution at http://www.greenlighttestprep.com/module/gre-arithmetic/video/1073 but mine should work too.

I thought there was a rule I learned in highschool that says if you have a tangent line then you get an isosceles triangle (so angle AOB = angle ADB). BUT I just looked it up and I'm wrong. It has to do with having 2 tangent lines from the same point. Back to studying!! Thanks though

The link isn't working for me

For this question (http://www.greenlighttestprep.com/module/gre-geometry/video/889) I understand the video solution however when I solved it, I used the fact that angle AOB = angle ADB to get A (50 degrees) as my answer. Not sure what happened

Thanks for your help TakerUK! To be honest I have A LOT of trouble reading math solutions. When I see the solutions in the official GRE book, I go cross eyed! I think I'm more of a visual learner (which is why I prefer videos :-)

Not sure if this forum is meant for solving GRE practice questions, but I see there are some experts here who can probably help. It's a geometry question, so I can't really transcribe the diagram - http://www.greenlighttestprep.com/module/gre-geometry/video/891 Is there are easier solution? What's the level of difficulty? They say it's a medium question.

I just found this free GRE course http://www.greenlighttestprep.com/ They have a lot of videos but I want to make sure it covers everything first. Anyone?