Question

tính:

Answer 1

\(=\dfrac{5.9.9}{8.9.5.3}=\dfrac{3}{8}\)

Answer 2

`(5 xx 81)/(72 xx 15)`

`= (5 xx 3^4)/(2^3 xx 3^2 xx  3 xx 5)`

`= (5 xx 3^3 xx 3)/(8 xx 3^3 xx 5)`

`= 3/8`

Answer 3

\(\dfrac{5x81}{72x15}=\dfrac{5x9x9}{8x9x3x5}=\dfrac{9}{24}=\dfrac{3}{8}\)

Answer 4

`(5 xx 81)/(72 xx 15)`

`= (5 xx 3 xx 3 xx 3 xx 3)/(8 xx 3 xx3 xx 3 xx 5)`

`= (cancel(5) xx cancel(3) xx cancel(3) xx cancel(3) xx 3)/(8 xx cancel(3) xx cancel(3) xx cancel(3) xx cancel(5))`

`= 3/8`