x ³ : (-1/2) ² = 1/2 b) (2:x-3/5) ² = 16 c )(1,5-3/5 x ) ³=27-1 d)7x3mũ x +20 x 3 mũ x =3 mũ 25 e ) ( 5x - 39) x7 +3,5 =21/2

`a) x^3 ÷ ( -1/2 )^2 = 1/2`

`=> x^3 ÷ 1/4 = 1/2`

`=> x^3 = 1/2 . 1/4`

`=> x^3 = 1/8`

`=> x^3 = ( 1/2 )^3`

`=> x = 1/2`

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`b) ( 2 ÷ x - 3/5 )^2 = 16`

`=> ( 2 ÷ x - 3/5 )^2 = 4^2`

`=> 2 ÷ x - 3/5 = 4`

`=> 2 ÷ x = 4 + 3/5`

`=> 2 ÷ x = 23/5`

`=> x = 2 ÷ 23/5`

`=> x = 10/23`

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`c)` bạn xem lại đề

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`d) 7 . 3^x + 20 . 3^x = 3^25`

`=> ( 7 + 20 ) . 3^x = 3^25`

`=> 27 . 3^x = 3^25`

`=> 3^3 . 3^x = 3^25`

`=> 3^x = 3^25 ÷ 3^3`

`=> 3^x = 3^22`

`=> x = 22`

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`e) ( 5x - 39 ) . 7 + 3,5 = 21/2`

`=> ( 5x - 39 ) . 7 + 7/2 = 21/2`

`=> ( 5x - 39 ) . 7 = 21/2 - 7/2`

`=> ( 5x - 39 ) . 7 = 7`

`=> 5x - 39 = 7 ÷ 7`

`=> 5x - 39 = 1`

`=> 5x = 1 + 39`

`=> 5x = 40`

`=> x = 40 ÷ 5`

`=> x = 8`