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14.5 Higher Degree Inequalities in One Variable 一元高次不等式
Solve the inequalities
解下列不等式
(1) (2 – x)(x + 1)(x – 3) 0
(2) (2x – 3)(x – 1)(x + 1)(x + 3) < 0
(3)(a) (x – 3)(x – 1)(x + 1)(x + 3) < 0
(3)(b) (x – 3)(x – 1)(x + 1)(x + 3) > 0
(3)(c) (x – 3)(x – 1)(x + 1)(x + 3) 0
(3)(d) (x – 3)(x – 1)(x + 1)(x + 3) 0
(4) (x + 2)(x – 2x – 4) > 0
(5) (1 – 2x)(x – 1)(x + 2x + 3) < 0
(6) (x + 4)(x + 2) > (3x – 2)(x + 2)
Answer :
(1) x –1, 2 x 3
(2) –3 < x < –1, 1 < x <
(3)(a) –1 < x < 1, 1 < x < 3
(3)(b) x < –3, –3 < x < –1, x > 3
(3)(c) –1 x 3, x = –3
(3)(d) x –1, x 3, x = 1
(4) -2 < x < 1 – , x > 1 +
(5) x < , x > 1
(6) x < –2, –2 < x < 3