Question

The value of $(8^{-25}-8^{-26})$ is

• A. $7\times 8^{-25}$
• B. $7\times 8^{-26}$
• C. $8\times 8^{-26}$
• D. None of these

Answer 1

The correct option is B $7\times 8^{-26}$

$(8^{-25}-8^{-26})$ $=(\frac{1}{8^{25}}-\frac{1}{8^{26}})$

$=\frac{8^{25}(8-1)}{8^{25}\times 8^{26}}$

$=\frac{(8-1)}{8^{26}}$

$=7\times 8^{-26}$

Thus option $\left(B\right)$ is correct.