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2x2 + 6 > 40 Which values of x satisfy the inequality above?
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27 Oct 2018, 06:52
27 Oct 2018, 06:52
2
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\(2x^2 + 6 > 40\)
Which values of x satisfy the inequality above?
Indicate all such values.
A. –8
B. –6
C. –4
D. –2
E. 2
F. 4
G. 6
H. 8
Which values of x satisfy the inequality above?
Indicate all such values.
A. –8
B. –6
C. –4
D. –2
E. 2
F. 4
G. 6
H. 8
ShowHide Answer
Official Answer
A,B,G,H
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: 2x2 + 6 > 40 Which values of x satisfy the inequality above?
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20 Dec 2019, 11:33
20 Dec 2019, 11:33
2
Carcass wrote:
\(2x^2 + 6 > 40\)
Which values of x satisfy the inequality above?
Indicate all such values.
A. –8
B. –6
C. –4
D. –2
E. 2
F. 4
G. 6
H. 8
Which values of x satisfy the inequality above?
Indicate all such values.
A. –8
B. –6
C. –4
D. –2
E. 2
F. 4
G. 6
H. 8
Given: \(2x^2 + 6 > 40\)
Subtract 6 from both sides: \(2x^2 > 34\)
Divide both sides by 2: \(x^2 > 17\)
This tells us that EITHER \(x > \sqrt{17}\) OR \(x < -\sqrt{17}\)
ASIDE: \(\sqrt{16}=4\) and \(\sqrt{25}=5\)
Since 17 is BETWEEN 16 and 25, we know that \(\sqrt{17}\) is BETWEEN 4 and 5.
So we can say, \(\sqrt{17}=\) 4.something
When we applied this to her earlier solution, we can say that EITHER x > 4.something OR x < -4.something
When we examine the answer choices we can see that -8, -6, 6 and 8 satisfy those conditions.
Answer: A, B, G, H
Cheers,
Brent
Re: 2x2 + 6 > 40 Which values of x satisfy the inequality above?
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02 Jul 2020, 01:01
02 Jul 2020, 01:01
2
2x^2+6>40
let's simplify to be x^2+3>20
X^2>17
This is easier to check the answers.
A -8 ==>> 64>17 good
B -6 ==> 36>17 good
C -4 ==> 16 no
D -2 ==> 4 no
the only answers are a,b,g,h
let's simplify to be x^2+3>20
X^2>17
This is easier to check the answers.
A -8 ==>> 64>17 good
B -6 ==> 36>17 good
C -4 ==> 16 no
D -2 ==> 4 no
the only answers are a,b,g,h
