a) 3/4x – 1/4= 2(x – 3)+1/4 b) 30℅x-x+5/6=49/2

Đáp án:

`a,`

`3/4x – 1/4 = 2 (x -3) + 1/4`

`⇔ 3/4x – 1/4 = 2x – 6 + 1/4`

`⇔ 3/4x – 1/4 = 2x – 23/4`

`⇔ 3/4x – 1/4 – 2x + 23/4 = 0`

`⇔ (3/4x – 2x) + (-1/4 + 23/4) = 0`

`⇔ -5/4x + 11/2 = 0`

`⇔ -5/4 = 0 – 11/2`

`⇔ -5/4 = -11/2`

`⇔ x = -11/2 : (-5/4)`

`⇔ x = 22/5`

`text{Vậy}` `x = 22/5`

`b,`

`30%x – x + 5/6 = 49/2`

`⇔ (30% – 1)x = 49/2 – 5/6`

`⇔ -7/10x = 71/3`

`⇔ x = 71/3 : (-7/10)`

`⇔ x = -710/21`

`text{Vậy}` `x=  (-710)/21`