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(p+5+p^3(-p-5))/(-p-5)=
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26 Feb 2021, 06:49
26 Feb 2021, 06:49
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\(\frac{p+5+p^3(-p-5)}{-p-5}=\)
A. \(p+5+p^3\)
B. \(P^3+5\)
C. \(p^3\)
D. \(p^3-1\)
E. \(p^3-5\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
A. \(p+5+p^3\)
B. \(P^3+5\)
C. \(p^3\)
D. \(p^3-1\)
E. \(p^3-5\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
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Re: (p+5+p^3(-p-5))/(-p-5)=
[#permalink]
26 Feb 2021, 07:06
26 Feb 2021, 07:06
Carcass wrote:
\(\frac{p+5+p^3(-p-5)}{-p-5}=\)
A. \(p+5+p^3\)
B. \(P^3+5\)
C. \(p^3\)
D. \(p^3-1\)
E. \(p^3-5\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
A. \(p+5+p^3\)
B. \(P^3+5\)
C. \(p^3\)
D. \(p^3-1\)
E. \(p^3-5\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
APPROACH #1:
Let's just focus on the NUMERATOR for a second.
Given: p + 5 + p³(-p - 5)
Factor -1 from the first part to get: -1(-p - 5) + p³(-p - 5)
So, we now have: -1(-p - 5) + p³(-p - 5)
Combine terms to get: (-1 + p³)(-p - 5)
Rearrange terms to get: (p³ - 1)(-p - 5)
Now replace ORIGINAL numerator with (p³ -1)(-p - 5)
We get: (p³ - 1)(-p - 5)/(-p - 5)
Simplify to get: (p³ - 1)
Answer: D
APPROACH #2:
We're looking for an expression that is equivalent to the original expression.
So if we evaluate the original expression for a particular value of p, then the equivalent expression should also yield the same value when we plug in the same value of p.
Let's test p = 1
Take: [p + 5 + p³(-p - 5)]/[-p - 5]
Replace p with 1 to get: [1 + 5 + 1³(-1 - 5)]/[-1 - 5]
Evaluate to get: 0/-6, which equals 0
So, when p = 1, the original express evaluates to be 0
Now let's plug p = 1 into the answer choices....
A. 1 + 5 + 1^3 = 7. No good, we want 0. ELIMINATE.
B. 1^3 + 5 = 6. No good, we want 0. ELIMINATE.
C. 1^3 = 1. No good, we want 0. ELIMINATE.
D. 1^3 - 1 = 0. Great - KEEP
E. 1^3 - 5 = -4. No good, we want 0. ELIMINATE.
Answer: D
Cheers,
Brent
Re: (p+5+p^3(-p-5))/(-p-5)=
[#permalink]
23 Jan 2023, 08:42
23 Jan 2023, 08:42
-p-5 !=0 than p != -5
than we can chose p=0 so eq=-1 and so when at D p=0 than D=-1
OPTION D
than we can chose p=0 so eq=-1 and so when at D p=0 than D=-1
OPTION D
