1) 25 - x^2 < 0
-x^2 < -25
x^2 > 25
x > 5
x < -5
x € (-беск; -5) U (5; +беск)
Ответ: 4)
2) 1/5; sqrt(5)/5; 1.5; 5/sqrt(5)
3) 2x^2 - 4(x + 4) = (3 - x)^2
2x^2 - 4x - 16 = 9 - 6x + x^2
2x^2 - x^2 - 4x + 6x - 16 - 9 = 0
x^2 + 2x - 25 = 0
a = 1, b = 2, c = -25