`a)3/7+1/2-17/7+3/2`

` =(3/7 -17/7)+(1/2+3/2)`

`=(-2)+2`

`=0`

``

`b)1/7+6/7.(1/2-1/3)`

`=1/75+6/7.(3/6-2/6)`

`=1/7 + 6/7. 1/6`

`=1/7 +1/7`

`=2/7`

``

`4/5 . 19 1/3 - 4/5 . 39 1/3`

`=4/5  . (19 1/3 - 39 1/3)`

`=4/5. (-20)`

`=-16`

``

`d)(-2)^3+(75%-0,25) : (2 1/4 - 1 5/6)`

`= (-8)+(0,75-0,25):(9/4-11/6)`

`=(-8)+0,5:(27/12-22/12)`

`=(-8)+0,5 : (5/12)`

`=(-8)+1/2 * 12/5`

`=(-8)+6/5`

`=(-8)+1,2`

`=-6,8`

`caty09`

 

Đáp án:

a) `0`

b) `2/7`

c) `-16`

d) `-(34)/5` 

Giải thích các bước giải:

a) `3/7+1/2-(17)/7+3/2`

`=(3/7-(17)/7)+(1/2+3/2)`

`=-(14)/7+4/2`

`=-2+2`

`=0`

b) `1/7+6/(7).(1/2-1/3)`

`=1/7+6/(7).(3/6-2/6)`

`=1/7+6/(7).(1)/6`

`=1/7+1/7`

`=2/7`

c) `4/(5).19(1)/3-4/(5).39(1)/3`

`=4/(5).(19(1)/(3)-39(1)/(3))`

`=4/(5).(-20)`

`=-16`

d) `(-2)^3+(75%-0,25):(2(1)/(4)-1(5)/(6))`

`=-8+(0,75-0,25):(9/4-(11)/6)`

`=-8+0,5:((54)/(24)-(44)/(24))`

`=-8+1/2:(5)/(12)`

`=-8+1/(2).(12)/5`

`=-8+6/5`

`=(-40)/5+6/5`

`=(-34)/5`