lm từ a đến h giúp ạa

a) \( \sqrt{(-7)^3} = \sqrt{-343} \)
Kết quả không xác định (số phức).

b) \( -\sqrt{-\left(\frac{1}{4}\right)^2} = -\sqrt{-\frac{1}{16}} = -\sqrt{\frac{1}{16}}i = -\frac{1}{4}i \)

c) \( -\left(-\sqrt{123}\right) = \sqrt{123} \)

d) \( \frac{4}{5} \left(\frac{5}{4}\right)^2 = \frac{4}{5} \cdot \frac{25}{16} = \frac{100}{80} = \frac{5}{4} \)

e) \( \frac{5}{3} \sqrt{9} - \frac{7}{2} \sqrt{\frac{32}{98}} + \sqrt{225} \)
\( = \frac{5}{3} \cdot 3 - \frac{7}{2} \cdot \frac{4}{7} + 15 \)
\( = 5 - 2 + 15 = 18 \)

f) \( 4 \sqrt{0.25} - \frac{20}{3} \sqrt{0.09} + \sqrt{\frac{1}{16}} \)
\( = 4 \cdot 0.5 - \frac{20}{3} \cdot 0.3 + \frac{1}{4} \)
\( = 2 - \frac{6}{3} + 0.25 = 2 - 2 + 0.25 = 0.25 \)

g) \( \sqrt{(6-2\sqrt{7})^2} = |6-2\sqrt{7}| \)
Vì \( 2\sqrt{7} \approx 5.29 < 6 \) nên \( |6-2\sqrt{7}| = 6-2\sqrt{7} \)

h) \( \sqrt{(4 - 3\sqrt{3})^2} = |4 - 3\sqrt{3}| \)
Vì \( 3\sqrt{3} \approx 5.20 > 4 \) nên \( |4 - 3\sqrt{3}| = 3\sqrt{3} - 4 \)