Đáp án:
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`a,`
`(-2/3)^x = (-8)/27`
`↔ (-2/3)^x = (-2/3)^3`
`↔ x=3`
Vậy `x=3`
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`b,`
`3/4 - (-1/2)^x = 1/2`
`↔ (-1/2)^x = 3/4 - 1/2`
`↔ (-1/2)^x=1/4`
`↔ (-1/2)^x = (-1/2)^2`
`↔x=2`
Vậy `x=2`
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`c,`
`(-5)/8 - 1/2 × (-3/2)^x =(-7)/4`
`↔ 1/2 × (-3/2)^x= (-5)/8 - (-7)/4`
`↔ 1/2 × (-3/2)^x=9/8`
`↔ (-3/2)^x=9/8 ÷ 1/2`
`↔ (-3/2)^x=9/8 × 2`
`↔ (-3/2)^x=9/4`
`↔ (-3/2)^x = (-3/2)^2`
`↔ x=2`
Vậy `x=2`
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`d,`
`3x^3 = -24`
`↔ x^3 = -24 ÷3`
`↔ x^3 =-8`
`↔x^3=(-2)^3`
`↔x=-2`
Vậy `x=-2`
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`e,`
`x^4 + 1/4 = 5/16`
`↔x^4 = 5/16 - 1/4`
`↔x^4=1/16`
`↔` \(\left[ \begin{array}{l}x^4=(\dfrac{1}{2})^4\\x^4=(\dfrac{-1}{2})^4\end{array} \right.\)
`↔` \(\left[ \begin{array}{l}x=\dfrac{1}{2}\\x=\dfrac{-1}{2}\end{array} \right.\)
Vậy `x=1/2` hoặc `x=(-1)/2`
