Question

Tính nhanh:
a) A= 6/7 + 1/7 . 2/7 +1/7. 5/7
b) A= 4/9 . 13/3 - 4/3 . 40/9
c) A= 5/7. 5/11 + 5/7 . 2/11 -5/7 . 14/11
giúp mik được ko??

Answer 1

a, \(A=\dfrac{1}{7}.6+\dfrac{1}{7}.\dfrac{2}{7}+\dfrac{1}{7}.\dfrac{5}{7}=\dfrac{1}{7}\left(6+\dfrac{2}{7}+\dfrac{5}{7}\right)=1\)

b, \(A=\dfrac{4}{3}.\dfrac{13}{9}-\dfrac{4}{3}.\dfrac{40}{9}=\dfrac{4}{3}\left(\dfrac{13}{9}-\dfrac{40}{9}\right)=-4\)

c, \(A=\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}.\dfrac{-7}{11}=-\dfrac{5}{11}\)

Answer 2

`A=6/7+[1/7(2/7+5/7)]`

`A=6/7+(1/7*1)`

`A=6/7+1/7`

`A=1`

~~~~~~~~~~~~~~~~~~~

`A=4/3*13/9-4/3*40/9`

`A=4/3(13/9-40/9)`

`A=4/3*(-3)`

`A=-4`

~~~~~~~~~~~~~~~~~~~

`A=5/7(5/11+2/11-14/11)`

`A=5/7(-7/11)`

`A=-5/11`

Answer 3

`A=6/7 + 1/7 . 2/7 + 1/7 . 5/7`

`A = 1/7 . 6 + 1/7 . 2/7 + 1/7 . 5/7`

`A = 1/7 . ( 6 + 2/7 + 5/7)`

`A=1/7 . ( 42/7 + 2/7 + 5/7)`

`A=1/7 . 7`

`A=1`

________________________

`A=4/9 . 13/3 - 4/3 . 40/9`

`A=(4.13)/(9.3) - (4.40)/(3.9)`

`A=(4.13-4.40)/(9.3)`

`A=(4.(13-40))/27`

`A=(4.(-27))/27`

`A=-4`

___________________________

`A = 5/7 . 5/11 + 5/7 . 2/11 - 5/7 . 14/11`

`A  =5/7 . ( 5/11 + 2/11 - 14/11)`

`A=5/7 . ((5+2-14)/11)`

`A=5/7 . (-7)/11`

`A=(5xx(-7))/(7xx11)`

`A=(-35)/77`

`A=(-5)/11`