РЕШЕНИЕ:

x²​−17x+72<0

x²​−17x+72=0
D = 289 – 4∙1∙72 = 289 – 288 = 1 = 1²
x₁ = (17 + 1) / 2 = 18/2 = 9
x₂ = (17 – 1) / 2 = 16/2 = 8

Ответ: 4

РЕШЕНИЕ:

25x² ≤ 4

25x²​ – 4 ≤ 0

(5x-2)(5x+2) ≤ 0

(5x-2)(5x+2) = 0
x = 2/5 = 0.4
x = –2/5 = –0.4

Ответ: 1

РЕШЕНИЕ:

25x²​<4

25x²​ – 4 < 0

(5x-2)(5x+2) < 0

(5x-2)(5x+2) = 0
x = 2/5 = 0.4
x = –2/5 = –0.4

Ответ: 3

РЕШЕНИЕ:

x^2​−6x−27>0

x^2​−6x−27 = 0
D = 36 – 4∙1∙( – 27) = 36 + 108 = 144 = 12²
x₁ = (6+12) / 2 = 18 / 2 = 9
x₂ = (6 –12) / 2 = –6 / 2 = –3

Ответ: 1

РЕШЕНИЕ:

8x−x²​>0

x(8-x) > 0

x(8-x) = 0
x = 0
x = 8

Ответ: 2

РЕШЕНИЕ:

x−x²​ < 0

x(1-x) < 0

x(1-x) = 0
x = 0
x = 1

Ответ: 1