a) 2 x (X + 3 ) + 136 = 250
2 x (X + 3 ) = 250 - 136
2 x ( X +3 ) = 114
X + 3 = 114 ÷ 2
X + 3 = 57
X = 57 -3
X = 54
b) (X+1/4 ) × 4/5 + 1/5 = 2/13
( X + 1/4 ) x 4/5 = 2/13 - 1/5
( X + 1/4 ) x 4/5 = -3/65
(X + 1/4 ) =-3/65 ÷ 4/5
(X + 1/4) = -3/52
X = -3/52 - 1/4
X = -4/13
c) TH1
3 . X - 4/60 = 1/3
3 . X = 1/3 + 4/60
3. X = 24/60
X = 24/60 ÷ 3
X = 2/15
TH2 :
{3.X - 4 }/60 = 1/3
3.X-4 = 1/3 × 60
3 . X - 4 = 20
3 .X = 20 + 4
3 . X = 24
X =24 ÷ 3
X = 8
chúc bạn học tốt :)