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The value of (13)3−43(13−8÷2)÷8−{2+6×9}\frac{(13)^3-4^3 }{(13 - 8 ÷ 2)}÷8-\{2+6×9\}(13−8÷2)(13)3−43​÷8−{2+6×9}​  is:
Question

The value of (13)343(138÷2)÷8{2+6×9}\frac{(13)^3-4^3 }{(13 - 8 ÷ 2)}÷8-\{2+6×9\}​  is:

A.

2118-\frac{211}8​​

B.

6858\frac{685}8​​

C.

2178-\frac{217}8​​

D.

6858-\frac{685}8​​

Correct option is A

Given:

133431382÷8{2+6×9}.\frac{13^3 - 4^3}{13 - \frac{8}{2}} \div 8 - \{2 + 6 \times 9\}.​​

Formula Used:

a3b3=(ab)(a2+ab+b2)a^3 - b^3 = (a - b)(a^2 + ab + b^2)​.

Solution: 

Simplifying terms separately:  
13343=(134)(132+13×4+42)=9×(169+52+16)=9×237=213313^3 - 4^3 = (13 - 4)(13^2 + 13 \times 4 + 4^2) = 9 \times (169 + 52 + 16) = 9 \times 237 = 2133

1382=134=913 - \frac{8}{2} = 13 - 4 = 9

So, 

133431382=21339=237\frac{13^3 - 4^3}{13 - \frac{8}{2}} = \frac{2133}{9} = 237 

237÷8=2378237 \div 8 = \frac{237}{8} 

2+6×9=2+54=562 + 6 \times 9 = 2 + 54 = 56  

Now, 

237856=2374488=2118\frac{237}{8} - 56 = \frac{237 - 448}{8} = \frac{-211}{8} 

Thus, the value of expression is 2118\frac{-211}{8} ​

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