Question

解不等式...

(1)3x^2-x-2<0
(2)2x^2-5x-3>0
(3)4x^2-4x-15>0
(4)2+3x-2x^2<0
(5)-x^2+2x-3x>0
(6)x^2-4x+4>0

Answer 1

1. (3x+2)(x-1)<0
那么-2/3<x<1

2. (x-3)(2x+1)>0
那么x>3或x<-1/2

3. (2x-5)(2x+3)>0
那么x>5/2或x<-3/2

4. 2x^2-3x-2>0
(x-2)(2x+1)>0
那么x>2或x<-1/2

5. x^2+x<0
x(x+1)<0
那么-1<x<0

6. (x-2)^2>0
那么x≠2

Answer 2

(1)3x^2-x-2<0
(3x+2)(x-1)<0

(2)2x^2-5x-3>0
(2x+1)(x-3)>0

(3)4x^2-4x-15>0
(2x+3)(2x-5)>0

(4)2+3x-2x^2<0
2x^2-3x-2>0
(2x+1)(x-2)>0

(5)-x^2+2x-3x>0
x^2+x<0
x(x+1)<0

(6)x^2-4x+4>0
(x-2)^2>0

Answer 3

(1)-2/3<x<1 (2)x>3，或x<-1/2 (3)x>5/2或x<-3/2 (4)x>2或x<-1/2 (5)-1<x<0 (6)x不等于2