Question

b^3/63x^4•7x^4/b^12
Пжжжж

Answer 1

$\dfrac{b^{3} }{63x^{4} } \cdot\dfrac{7x^{4} }{b^{12} } =\dfrac{b^{3}\cdot 7 }{7\cdot 9\cdot b^{3} \cdot b^{9} } =\boxed{\dfrac{1}{9b^{9} } }$