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Consider the function f(x) = x 2 – 5x. For which value(s) of
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20 Jul 2019, 02:50
20 Jul 2019, 02:50
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Consider the function \(f(x) = x^2 – 5x\). For which value(s) of x does \(f(x) = 14\)?
Indicate all that apply.
A. 19
B. 14
C. 7
D. 2
E. 0
F. –2
G. –7
Indicate all that apply.
A. 19
B. 14
C. 7
D. 2
E. 0
F. –2
G. –7
Retired Moderator
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Posts: 6218
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Re: Consider the function f(x) = x 2 – 5x. For which value(s) of
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20 Jul 2019, 05:16
20 Jul 2019, 05:16
Carcass wrote:
Consider the function \(f(x) = x^2 – 5x\). For which value(s) of x does \(f(x) = 14\)?
Indicate all that apply.
A. 19
B. 14
C. 7
D. 2
E. 0
F. –2
G. –7
Indicate all that apply.
A. 19
B. 14
C. 7
D. 2
E. 0
F. –2
G. –7
We are looking for values of x so that \(f(x) = 14\)
In other words, we want values of x so that \(x^2 – 5x = 14\)
This is a quadratic equation, so we should first set it equal to zero
Subtract 14 from both sides to get: \(x^2 – 5x - 14 = 0\)
Factor to get: \((x - 7)(x + 2) = 0\)
So, EITHER \((x - 7) = 0\) OR \((x + 2) = 0\)
If \((x - 7) = 0\), then \(x = 7\)
If \((x + 2) = 0\), then \(x = -2\)
Answer: C and F
Cheers,
Brent
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Joined: 02 Jan 2020
Status:GRE Quant Tutor
Posts: 1115
Given Kudos: 9
Location: India
Concentration: General Management
Schools: XLRI Jamshedpur, India - Class of 2014
GMAT 1: 700 Q51 V31
GPA: 2.8
WE:Engineering (Computer Software)
Re: Consider the function f(x) = x 2 – 5x. For which value(s) of
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06 Jan 2022, 10:47
06 Jan 2022, 10:47
1
Given that \(f(x) = x^2 – 5x\) and we need to find those values of x for which \(f(x) = 14\)
f(x) = 14
=> \(x^2 – 5x = 14\)
=> \( x^2 - 5x - 14 = 0\)
=> \( x^2 - 7x + 2x - 14 = 0\)
=> x(x-7) +2(x-7) = 0
=> (x-7)*(x+2) = 0
=> x = -2, 7
So, Answer will be C and F
Hope it helps!
Watch the following video to learn the Basics of Functions and Custom Characters
f(x) = 14
=> \(x^2 – 5x = 14\)
=> \( x^2 - 5x - 14 = 0\)
=> \( x^2 - 7x + 2x - 14 = 0\)
=> x(x-7) +2(x-7) = 0
=> (x-7)*(x+2) = 0
=> x = -2, 7
So, Answer will be C and F
Hope it helps!
Watch the following video to learn the Basics of Functions and Custom Characters
