Question

If 3x+ 2/x =7, then = (9x² - 4/x²) =
A. 25
B. 35
C. 49
D. 30

Answer 1

Answer:

answer is 35 .............

Answer 2

Given : 3x + 2/x = 7

To find : value of  9x² -  4/x²

 

Solution :  

3x + 2/x = 7

3x² + 2 = 7x  

3x² - 7x + 2 = 0

3x² - 6x - x + 2 = 0

[By middle term splitting]

3x(x - 2) - 1(x - 2) = 0

(3x - 1) (x - 2) = 0

x = ⅓ (neglected) or x = 2  

Now,  

On putting x = 2 in  9x² - 4/x²  :

9x² -  4/x² = 9(2)² - 4/2²

= 9 × 4 - 4/4

= 36 - 1

= 35

9x² -  4/x² = 35  

Hence the value of 9x² - 4/x²  is 35.

Among the given options option (B) 35 is correct.

HOPE THIS ANSWER WILL HELP YOU…..

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