Ai làm nhanh sẽ dc hay nhất! Mình cho nhiều điểm Bài 1: a) 3*(-5)/11 b) 3/5+4/7*14/6 c) 10/21-3/8*4/15 d) (2/3+3/4)*(5/7+5/14) Bài 2: a) x-1/5=7/11*3/21 b) x/25=(-3)/15*7/6 c) x+7/59/8*4/27 d) x:5/11=(-4)/12*6 e) x-1/2=3/10*5/6 f) x/5=(-3)/14*7/3 g)x+2/3=9/15*5/27 h)x:4/11=11/4*2

`1)`

`a)`

`3*(-5)/11=(3.(-5))/11=(-15)/11`

`b)`

`3/5+4/7*14/6=3/5+(4.14)/(7.6)=3/5+(4.2.7)/(3.2.7)=3/5+4/3=(9+20)/15=29/15`

`c)`

`10/21-3/8*4/15=10/21-(3.4)/(8.15)=10/21-(2.2.3)/(2.5.2.2.3)=1/10`

`d)`

`(2/3+3/4).(5/7+5/14)=(8/12+9/12)*(10/14+5/14)=17/12.(15)/14=(17.5.3)/(14.4.3)=(17.5)/14.4=85/56`

`2)`

`a)`

`x-1/5=7/11*3/21`

`x-1/5=(7.3)/(11.21)`

`x-1/5=(7.3)/(11.7.3)`

`x-1/5=(1)/(11)`

`x=(1)/(11)+1/5`

`x=(5)/(55)+11/55=16/55`

`b)`

`x/25=(-3)/15*7/6`

`x/25=(-3)/15*7/3.2`

`x/25=(-1)/15*7/2`

`x/25=(-7)/30`

`x=(-7.25)/30`

`x=(-7.5.5)/(6.5)`

`x=(-7.5)/(6)=(-35)/6`

`c)`

`d)`

` x:5/11=(-4)/12*6`

` x:5/11=(-4.6)/12`

` x:5/11=(-2.2.6)/(2.6)`

` x:5/11=-2`

` x=-2.(5)/11`

` x=(-10)/11`

`e)`

`x-1/2=3/10*5/6`

`x-1/2=(3.5)/(10.6)`

`x-1/2=(3.5)/(5.2.3.2)`

`x-1/2=(1)/(4)`

`x=(1)/(4)+1/2=1/4+2/4=3/4`

`f)`

` x/5=(-3)/14*7/3`

` x/5=(-3.7)/(14.3)`

` x/5=(-1.3.7)/(7.3.3)`

` x/5=(-1)/(3)`

` x=(-1.5)/(3)`

` x=(-5)/(3)`

`g)`

`x+2/3=9/15*5/27`

`x+2/3=(9.5)/(15.27)`

`x+2/3=(3.3.5)/(3.5.3.9)`

`x+2/3=(1)/(9)`

`x=(1)/(9)-2/3`

`x=(1)/(9)-6/9=(-5)/9`

`h)`

`x:4/11=11/4*2`

`x:4/11=11/2`

`x=11/2.(4)/11`

`x=11/2.(2.2)/11`

`x=2`