Question

求同时满足不等式x方-2x<8和x方-2x≥3的整数解集合

Answer 1

x²-2x＜8 x²-2x-8＜0 (x-4)(x+2)＜0 -2＜x＜4
x²-2x≥3 x²-2x-3≥0 (x-3)(x+1)≥0 x≤-1或x≥3
∴-2＜x≤-1或3≤x＜4
∴整数解集合﹛-1,3﹜

Answer 2

x方-2x<8
x^2-2x-8<0
(x-4)(x+2)<0
-2<x<4

x方-2x≥3
x^2-2x-3≥0
(x-3)(x+1)≥0
x≥3 或x≤-1
所以 -2<x≤-1 或 4>x≥3

整数解为：x=-1或3

Answer 3

x方-2x<8
x²-2x-8<0
(x+2)(x-4)<0
-2<x<4
x方-2x≥3
即
x方-2x-3≥0
（x+1）（x-3）≥0
x≤-1或x≥3
所以
整数解为：x=-1或3.

Answer 4

x方-2x<8 x^2-2x-8<0 -2<x<4
x方-2x≥3 x^2-2x-3>=0 x<=-1或x>=3
取交集得
-2<x<=-1或3<=x<4
整数解集合{-1,3}