c)5/2-X+4/5=2/3-(-4/7) d)3/7x-2/3x=10/21 e)7/35 : (x-1/30=-2/25

`#BanhMii`

Đáp án:

Giải thích các bước giải:

 `c) 5/2 - x + 4/5 = 2/3 - (-4/7)`
`=> 5/2 - x + 4/5 = 2/3 + 4/7`

`=> -x = 2/3 + 4/7 - 4/5 - 5/2`

`=> -x = 140/210 + 120/210 - 168/210 - 525/210`

`=> -x = -433/210`

`=> x = 433/210`

Vậy: `x = 433/210`

`d) 3/7x - 2/3x = 10/21`

`=> (3/7 - 2/3)x = 10/21`

`=> (-5/21)x = 10/21`

`=> x = 10/21 : (-5/21)`

`=> x = 10/21. (-21/5)`

`=> x = -2`

Vậy: `x = -2`

`e) 7/35 : (x - 1/30) = -2/25`

`=> x - 1/30 = 7/35 : (-2/25)`

`=> x - 1/30 = 1/5. (-25/2)`

`=> x - 1/30 = -5/2`

`=> x = -5/2 + 1/30`

`=> x = -75/30 + 1/30`

`=> x = -74/30`

`=> x = -37/15`

Vậy: `x = -37/15`