3. Решите уравнение: a) 9 - x² = 0 б) 16y² - 25 = 0 в) (4-x)² - x(x+6,5) = 16

Решение:

1. \( 9 - x^2 = 0 \) \(     x^2 = 9 \) \(     x = ± 3 \)
2. \( 16y^2 - 25 = 0 \) \(     16y^2 = 25 \) \(     y^2 = \frac{25}{16} \) \(     y = ± \frac{5}{4} = ± 1.25 \)
3. \( (4-x)^2 - x(x+6.5) = 16 \)
   \( (16 - 8x + x^2) - (x^2 + 6.5x) = 16 \)
   \( 16 - 8x + x^2 - x^2 - 6.5x = 16 \)
   \( 16 - 14.5x = 16 \)
   \( -14.5x = 0 \)
   \( x = 0 \)

Ответ: а) \( x = ± 3 \); б) \( y = ± 1.25 \); в) \( x = 0 \).