Ответ:

x∈ (-4,0) U (1/4, 7)

Пошаговое объяснение:

4x²-x > 0,

х² - 3х – 28 < 0

x(4x-1) > 0

x > 0

4x-1 > 0

4x > 1

x > 1/4

x∈(-∞,0) U (1/4, +∞)

х² - 3х – 28 < 0

D = -3²-4*(-28) = 9+112= 121

x1 = 3+11/2 = 7

x2 = 3-11/2 = -4

(x+4)(x-7) < 0

x∈ (-4,7)

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-4. 0. 1/4. 7

x∈ (-4,0) U (1/4, 7)