Tìm x, biết: a) \( 2 - \sqrt{x} = -7 \) (x ≥ 0), b) \( 25 - \sqrt{x - 5} = 9 \) (x ≥ 5)

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Bài 7. Tìm x, biết:
a) \( 2 - \sqrt{x} = -7 \) (x ≥ 0)
b) \( 25 - \sqrt{x - 5} = 9 \) (x ≥ 5)
c) \( \frac{2}{9}(x + 1)^2 = -\frac{23}{9} \)
d) \( 3\sqrt{x + 1} - \frac{1}{4} = 5 \) (x ≥ -1)
e) \( \frac{1}{5}\sqrt{3x + 2} = 1 \) (x ≥ -\frac{2}{3})
f) \( (\sqrt{2x + 1} - 4)(5 + \sqrt{x}) = 0 \) (x ≥ 0)

Bài 8. Tìm x, biết:
a) \( |x + 3| = -\frac{5}{6} \) (3)
b) \( \frac{1}{2}|2x + 1| = -\sqrt{0.25} \)
c) \( (4 - 3|x|)(5 + |x|) = 0 \)
d) \( |x + 1| = 3 - x \)
e) \( |x + 1| = \frac{1}{4} - \left( \frac{1}{4} \right)^3 \)
f) \( |2x - 1| - |0.5x + 1| = 0 \)