Đáp án:
$B=-1$
Giải thích các bước giải:
$B=\dfrac{1}{-77}\cdot7^4.(-11)^2.77^4\cdot\left(\dfrac{1}{7^2}\right)^2:(7^3. 11^5)\\\Rightarrow B=\dfrac{1}{-77}\cdot7^4.11^2.11^4.7^4\cdot\dfrac{1}{7^4}:7^3:11^5\\\Rightarrow B=\dfrac{-1}{77} \cdot7^4.11\cdot\dfrac{7^4}{7^4}:7^3\\\Rightarrow B=\dfrac{-1}{77}\cdot7.11\\\Rightarrow B=\dfrac{-1}{7}\cdot 7\\\Rightarrow B=-1$
Vậy $B=-1$.