Struggling almost every math question i come across

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I have enrolled in the veritas classes and gmat prep now modules but I can not get a good understanding of the quantitative section. I pretty much struggle on every quantitative question. Do you guys have any suggestions on how i could improve on the quantitative section? Also here is a question i am struggling on. Please help me solve it!!!

if (b-3)(4+2/b)=0 and b is not equal to 3, then b=

A) -8
b) -2
c) -1/2
d) 1/2
e) 2
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by Brent@GMATPrepNow » Sun Nov 17, 2013 5:10 pm
kathleen1986 wrote: if (b-3)(4+2/b) = 0 and b is not equal to 3, then b=

A) -8
b) -2
c) -1/2
d) 1/2
e) 2
I think you incorrectly transcribed the part in red.
EDIT: Thanks to riz_gmat, I realize that we just need a space in the original question. I've provided a full solution further down this thread.

I forget the original wording of the question, but here's a hint to get you started:

General Principle tested: If (something)(something else) = 0, then something = 0, or something else = 0
For example, if (x + 2)(x - 5) = 0, then x + 2 = 0, or x - 5 = 0

Cheers,
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Last edited by Brent@GMATPrepNow on Tue Nov 19, 2013 7:55 am, edited 1 time in total.
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by Brent@GMATPrepNow » Sun Nov 17, 2013 5:12 pm
kathleen1986 wrote:I pretty much struggle on every quantitative question. Do you guys have any suggestions on how i could improve on the quantitative section?
To improve your quantitative skills, I believe that you should compartmentalize your learning and take the time to master each topic (e.g., percents, ratios, exponents, statistics, etc.). This means that, for each topic, you should:
1) Learn the underlying concepts (rules, attributes, notation, etc.)
2) Learn GMAT-specific strategies related to that topic
3) Practice dozens of questions all related to that one topic.
4) Don't stop working on that topic until you have mastered it
Then, and only then, move on to the next topic.

To help you focus on one topic at a time, you can use BTG's tagging feature. For example, here are all of the questions tagged as statistics questions: https://www.beatthegmat.com/forums/tags/ ... statistics
See the left side of that linked page for more tag options.

While completing questions from the Official Guide (OG), you should you use an Error Log (aka Improvement Chart) You can find a free downloadable Improvement Chart here: https://www.beatthegmat.com/mba/gmat-error-log. This will help you identify and strengthen your weak areas.

You should also spend a lot of time reviewing the responses from the Experts on this site. They model the steps one should take when tackling math problems.

I hope that helps.

Cheers,
Brent
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by kathleen1986 » Mon Nov 18, 2013 6:44 am
Thank you so much for the tips!

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by Brent@GMATPrepNow » Mon Nov 18, 2013 6:56 am
Glad to help.

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by riz_gmat » Mon Nov 18, 2013 8:57 pm
(b-3) ( 4 + 2/b) = 0

(b-3) ( 4b + 2 ) = 0 * b = 0

Either b = 3 or b = -2/4 = -1/2
b cannot be 3 ( given in ques) , so[spoiler] b = -1/2[/spoiler]

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by Brent@GMATPrepNow » Tue Nov 19, 2013 7:52 am
kathleen1986 wrote: if (b - 3)(4 + 2/b) = 0 and b is not equal to 3, then b =

A) -8
b) -2
c) -1/2
d) 1/2
e) 2
Thanks riz_gmat. I didn't realize that the question just needed a space to for it to make sense :-)

General Principle tested: If (something)(something else) = 0, then something = 0, or something else = 0
So, we have (b - 3)(4 + 2/b) = 0,
We can conclude that (b - 3) = 0, or (4 + 2/b) = 0
If (b - 3) = 0, then b = 3
If (4 + 2/b) = 0, then 2/b = -4, which means b = -1/2

Since we're told that b ≠ 3, we can conclude that b = [spoiler]-1/2[/spoiler]
Answer = C

Cheers,
Brent
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by Mathsbuddy » Tue Nov 19, 2013 8:22 am
if (b - 3)(4 + 2/b) = 0 and b is not equal to 3, then b =

Anything * 0 = 0

so either (b-3) = 0
or (4 + 2/b) = 0

Solve each of these 2 equations to get 2 possible answers for b.
One is in the list.

I hope that helps.