Question

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Tìm x biết:

a, 5x+2>3x-1

b, \(\dfrac{3}{4}.x-\dfrac{1}{2}>\dfrac{1}{2}.x+\dfrac{3}{4}\)

c, (x-2).(x-3)>0

d, (2x+4)(x-5)<0

Answer 1

[Nguyễn Lê Phước Thịnh]

a: 5x+2>3x-1

=>5x-3x>-1-2

=>2x>-3

hay x>-3/2

b: \(\dfrac{3}{4}x-\dfrac{1}{2}>\dfrac{1}{2}x+\dfrac{3}{4}\)

=>3/4x-1/2x>3/4+1/2

=>1/2x>5/4

hay x>5/4:1/2=5/2

c: (x-2)(x-3)>0

=>x-3>0 hoặc x-2<0

=>x>3 hoặc x<2

d: (2x+4)(x-5)<0

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

=>-2<x<5