a) 3/5 . x - 2/3 = -1/2 b) (1/2 - x) . 2/3 = 1/8
3/5 . x = -1/2 + 2/3 1/2 - x = 1/8 : 2/3
3/5 . x = 1/6 1/2 - x = 3/16
x = 1/6 : 3/5 x = 1/2 -3/16
x = 5/18 x = 5/16
Vậy x = 5/18 Vậy x = 5/16
c) | 2.x - 3/7 | - 1/2 = 3/4
| 2.x - 3/7 | = 3/4 + 1/2
| 2.x - 3/7 | = 5/4
TH1 : 2.x - 3/7 = 5/4 TH2: 2.x - 3/7 = -5/4
2.x = 5/4 + 3/7 2.x = -5/4 + 3/7
2.x = 47/28 2.x = -23/28
x = 47/28 : 2 x = -23/28 : 2
x = 47/56 x = -23/56
Vậy x ∈ { 47/56 ; -23/56 }
d) 2.x +$\frac{1}{3}$ = x - $\frac{5}{2}$
$\frac{6x + 1}{3}$ = $\frac{2x - 5}{2}$
2(6x + 1) = 3(2x - 5)
12x + 2 = 6x - 15
6x - 12x = 15 + 2
-6x = 17
x = 17 : -6
x = $\frac{-17}{6}$
Vậy x = $\frac{-17}{6}$