If x 0 and 2x^2 + 6x = 8, then the average (arithmetic mean) of x +

Question

If x > 0 and 2x^2 + 6x = 8, then the average (arithmetic mean) of x + 2, 2x – 1, and x + 4 is equal to which of the following?

A. –2 
B. 3 
C. 3.5 
D. 5 
E. 7

tam87 · Answer

2x^2 + 6x - 8 = 0
or, x^2 + 3x - 4 = 0
or, (x + 4) (x - 1) = 0
As x > 0, x = 1

mean of the terms = 1/3   = 1/3   = 1/3   = 3 (Choice B)

BrentGMATPrepNow · Answer

Given: 2x² + 6x = 8
Divide both sides by 2 to get: x² + 3x = 4
Subtract 4 from both sides to get: x² + 3x - 4 = 0
Factor: (x + 4)(x - 1) = 0
Solved to get: EITHER x = -4 OR x = 1

Since we're told that x > 0, we can be certain that  x = 1

QUESTION: What is the average (arithmetic mean) of x + 2, 2x – 1, and x + 4? 
If  x = 1 , then: 
x + 2 =  1  + 2 =  3 
2x - 1 = 2( 1 ) - 1 =  1 
x + 4 =  1  + 4 =  5

Average of  3 ,  1  and  5  = ( 3  +  1  +  5 )/3
= 9/3
= 3

Answer: B

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 https://www.youtube.com/watch?v=Y9f_0QJU1ug

Abhishek009 · Answer

2x^2 + 6x = 8

Solve the Quadratic Equation, we have  x = 1  ,  -4  ; further since it is given  x > 0  , we are left with x = 1

Average of  x + 2 ,  2x – 1 , and  x + 4  is  \frac{( x + 2 ) + ( 2x – 1 ) + ( x + 4 )}{3} = \frac{4x + 5}{3} = \frac{9}{3} = 3 , Answer must be (B) 3

dollytaneja51 · Answer

2x^2 + 6x = 8
x^2 + 3x = 4
(x-1) (x+4) = 0
Its given in the ques x>0
Therefore, x = 1

Now (x+2)+(2x-1)+(x+4)/3
(4x+5)/3
Putting x = 1
4(1)+5/3
3 
B is the answer

Posted from my mobile device

ScottTargetTestPrep · Answer

Let’s solve the given equation:

2x^2 + 6x - 8 = 0

x^2 + 3x - 4 = 0

(x - 1)(x + 4) = 0

x = 1 or x = -4

Since we are given that x > 0, then x = 1. So the average of x + 2, 2x – 1, and x + 4 is equal to

(3 + 1 + 5)/3 = 9/3 = 3

Answer: B

BrushMyQuant · Answer

Theory: Average =  \frac{Sum Of All The Values}{Total Number Of Values}

We need to find the average (arithmetic mean) of x + 2, 2x – 1, and x + 4 
Total Number of Values= 3
Sum of All the Values= x+2 + 2x-1 + x + 4 = x + 2x + x + 2 -1 +4 = 4x + 5

Average =  \frac{Sum Of All The Values}{Total Number Of Values}  =  \frac{4x+5}{3}

Let's solve for x now

x > 0  and  2x^2 + 6x = 8 
=>  2x^2 + 6x - 8 = 0 
Divide both sides by 2 we get
  x^2 + 3x - 4 = 0 
=>  x^2 - x + 4x - 4 = 0 
=>  x(x - 1) + 4(x - 1) = 0 
=>  (x - 1) (x+ 4) = 0  
=> x = 1, -4
Since, x > 0
=> x = 1

=> Average =  \frac{4x+5}{3}  =  \frac{4*1+5}{3}  =  \frac{9}{3}  = 3

So,  Answer will be B 
Hope it helps!

To learn more about Statistics watch the following video

https://www.youtube.com/watch?v=Cvy_HHw4KIs

bumpbot · Answer

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If x > 0 and 2x^2 + 6x = 8, then the average (arithmetic mean) of x +

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