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What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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Updated on: 03 Feb 2019, 02:15
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What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ? A. 7 B. 3 C. 1 D. 3 E. 7
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Originally posted by Nums99 on 02 Feb 2019, 06:24.
Last edited by Bunuel on 03 Feb 2019, 02:15, edited 1 time in total.
Renamed the topic and edited the question.



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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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02 Feb 2019, 06:58
Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 +bx +3 ? a) 7 b)3 c)1 d)3 e)7
please help!!! If some expression is a factor of a quadratic equation, this means that it will satisfy it 2x1=0 x=1/2 Put the value of x in the quadratic equation 1/2 + b/2 + 3 =0 b = 7
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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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02 Feb 2019, 08:57
Quadratic equation 2x^+bx+3 = 0 Factors (2x1)*(2nd factor) = 2x^+bx+3= 0 (2x1) = 0 ==>> x = 1/2 plug in value of x into quadratic equation to determine value of b. You can take it from here. Give me Kudos to get my GMAT club test access**** Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 +bx +3 ? a) 7 b)3 c)1 d)3 e)7
please help!!!
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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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02 Feb 2019, 10:33
According to the Q: 2x − 1 =0 ==>\(x=\frac{1}{2}\) Hence \(b=2x\frac{3}{x}\) =13.2 = 7 Ans AJust 1 point Nums99 .... in the Q you mentioned an expression not an equation. To clarify : 2x^2 +bx +3 is an expression & on contracy 2x^2 +bx +3 =0 is an equation. All the solutions are done assuming you mentioned an eqn: 2x^2 +bx +3 =0 If the Q is about only the expression .....in my view the Q does not stand
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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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02 Feb 2019, 11:25
Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 +bx +3 ? a) 7 b)3 c)1 d)3 e)7
please help!!! If 2x1 is a factor, then it means that 2x1=0 ==> x=1/2 Now put x=1/2 in the equation 2x^2+bx+3=0 2*1/4+1/2b+3=0 Solving, b=7 Ans:A
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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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20 Feb 2019, 09:31
Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
A. 7 B. 3 C. 1 D. 3 E. 7 If someone got stuck and could not proceed as per the solutions mentioned above then you may work backward; One could use answer options and substitute for the value of b. Since 2x1 is a factor, you would realize that only option A works.
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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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22 Feb 2019, 14:38
CAMANISHPARMAR wrote: Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
A. 7 B. 3 C. 1 D. 3 E. 7 If someone got stuck and could not proceed as per the solutions mentioned above then you may work backward; One could use answer options and substitute for the value of b. Since 2x1 is a factor, you would realize that only option A works. Hello CAMANISHPARMAR ! Do you mean like this? 2x^2  7x + 3 2x^2  6x  x + 3 2x(x3) 1(x3) (2x1)(x3)? Thank you so much in advance!



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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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23 Feb 2019, 06:09
jfranciscocuencag wrote: CAMANISHPARMAR wrote: Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
A. 7 B. 3 C. 1 D. 3 E. 7 If someone got stuck and could not proceed as per the solutions mentioned above then you may work backward; One could use answer options and substitute for the value of b. Since 2x1 is a factor, you would realize that only option A works. Hello CAMANISHPARMAR ! Do you mean like this? 2x^2  7x + 3 2x^2  6x  x + 3 2x(x3) 1(x3) (2x1)(x3)? Thank you so much in advance! Hi jfranciscocuencag, Yes above method is correct. Given \((2x  1)\) is factor of \((2x1)(x3)\). Hence \(b = 7\) will be the answer. Answer A



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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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23 Feb 2019, 09:53
jfranciscocuencag wrote: CAMANISHPARMAR wrote: Nums99 wrote: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
A. 7 B. 3 C. 1 D. 3 E. 7 If someone got stuck and could not proceed as per the solutions mentioned above then you may work backward; One could use answer options and substitute for the value of b. Since 2x1 is a factor, you would realize that only option A works. Hello CAMANISHPARMAR ! Do you mean like this? 2x^2  7x + 3 2x^2  6x  x + 3 2x(x3) 1(x3) (2x1)(x3)? Thank you so much in advance! Yes, you got it right. You will get 2x1 as a factor only when b = 7
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Re: What is the value of b If 2x − 1 is a factor of 2x^2 + bx + 3 ?
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