Thực hiện phép tính

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7. |x-2|-3=5
8. \(\frac{1}{12} \cdot \frac{4}{21} = 3^{-\frac{1}{2}} \cdot (3x-2)\)
11. \((x - \frac{2}{9})^3 = (\frac{8}{27})^3\)
12. \(2 \cdot 3^x - 405 = 3^{x-1}\)
13. \(\left(\frac{3}{4}\right)^x = \frac{2^x}{3^x}\)
14. \((5x + 1)^2 = \frac{36}{49}\)
15. \(\left[(-0.5)^3\right]^x = \frac{1}{64}\)