Question

Rút gọn phân số sau:

\(\dfrac{21.9}{7.6.-7.3}\)

Answer 1

\(\dfrac{21\cdot9}{7\cdot6-7\cdot3}\\ =\dfrac{21\cdot9}{7\cdot\left(6-3\right)}\\ =\dfrac{21\cdot9}{7\cdot3}\\ =\dfrac{21\cdot9}{21}=9\)