Question

1/7+-9/27+10/7+-4/7

1,3 x2 1/4 -1,3 X31/4

1/4: x = 2,4 -4/5

5/4 ( x- 3/5)= -1/8

Answer 1

`1/7+(-9/27)+10/7+(-4/7)`

`= (1/7 + (-4)/7+10/7) +(-9/27)`

`= 7/7 +(-9/27)`

`= 1 +(-9/27)`

`= 27/27 + (-9/27)`

`=18/27`

`=2/3`

__

`1,3 xx2 1/4 -1,3 xx3 1/4`

`= 1,3 xx 9/4 -1,3 xx 13/4`

`=1,3 xx (9/4-13/4)`

`=1,3xx(-4)/4`

`=1,3 xx (-1)`

`=-1,3`

__

`1/4: x = 2,4 -4/5`

`=> 1/4 : x= 12/5 -4/5`

`=> 1/4 : x=8/5`

`=> x=1/4 : 8/5`

`=> x= 1/4 xx 5/8`

`=> x= 5/32`

__

`5/4 ( x- 3/5)= -1/8`

`=> x-3/5 = -1/8 : 5/4`

`=> x-3/5 = -1/8 xx 4/5`

`=> x-3/5 =-4/40`

`=> x-3/5 =-1/10`

`=> x=-1/10 +3/5`

`=> x=-1/10 + 6/10`

`=> x= 5/10`

`=>x=1/2`

` @ yngoc`