gmat Maths Study Guide 6.7

[reiserchen]

(1) Practice Problem
Solve using the quadratic equation and by factoring: 2x² + 3x + 1 = 0. Are the answers for each method the same?

a) I went through the quadratic equation and x = -1/2 which is right:o and 2nd result is -1 which is wrong..:test:.
So could you please explain again step by step, how to calculate?

b) How do you use the factoring solution in that case? I have just no idea?!:confused:

Thanks in advance!
Best regards
reiserchen

[reiserchen]

A pitty no one answered the question to me as it caused a lot of concerns to me...:confused:

Anyhow, may I add, that there is a typo in your book, as my solutions are X = -1 and -1/2 and they are correct! :applause:
Unfortunately the book says -1/2 and -5/2...:test:
cheerio
wolfgang

[kevin]

(1) Practice Problem
Solve using the quadratic equation and by factoring: 2x² + 3x + 1 = 0. Are the answers for each method the same?

a) I went through the quadratic equation and x = -1/2 which is right:o and 2nd result is -1 which is wrong..:test:.
So could you please explain again step by step, how to calculate?

b) How do you use the factoring solution in that case? I have just no idea?!:confused:

Thanks in advance!
Best regards
reiserchen

Factoring: 2x² + 3x + 1 = (2x +2)(2x +1)/2 = (x+1)(2x + 1) = 0
x is either -1 or - 1/2

Q formula: x = (- 3 +- sqrt(1))/2(2)
i.e. x is either -1 or -1/2

[kevin]

I apologize for not answering earlier:

If you do post questions and do not get a response, email me at
kma@manhattanreview.com so that you will get a timely answer!