tìm x , biết a, 3/35 - (3/5 - x ) = 2/7 b, ( x + 1/2 ) . ( 2x + 1 ) = 0 c, ( 4/15 - 1/6 ) . x = 3/4 . 8 /27

Bạn tham khảo!
b) (x + 1/2) . (2x + 1) = 0
⇒ x + 1/2 = 0 or 2x + 1 = 0
⇒ x = 0 - 1/2 or 2x = 0 + 1
⇒ x = -1/2 or 2x = 1
⇒ x = -1/2 or x = 1 : 2
⇒ x = -1/2 or x = 1/2
Vậy x = -1/2 or x = 1/2
c) (4/15 - 1/6) . x= 3/4 . 8/27
⇒ 1/10 . x = 3/4 . 8/27
⇒ 1/10 . x = 2/9
⇒ x = 2/9 : 1/10
⇒ x = 2.9 . 10/1
⇒ x= 20/9
Vậy x = 20/9
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