1)đề
=>3(7x-3)=2(x-1)
<=>21x-9=2x-2
<=>21x-2x=-2+9
<=>19x=7
<=>x=7/19
2)đề
<=>3=2x+3/x+1 +x-1/x+1
<=>3=3x+2/x+1
=>3(x+1)=3x+2
<=>3x+3=3x+2
<=>1=0 vôli
3)1/x-2 +4=2x-3/x-2
<=>4=2x-3/x-2 -1/x-2
<=>4=2x-4/x-2
<=>4=2(x-2)/x-2=2 (vô lí)
4)5/x-2 +6/3-4x=0
<=>5/x-2=6/4x-3
=>5(4x-3)=6(x-2)
<=>20x-15=6x-12
<=>20x-6x=15-12
<=>14x=3
<=>x=3/14
5)đề
=>(4x+7)(3x+4)=(12x+5)(x-1)
<=>12x^2+21x+16x+28=12x^2+5x-12x-5
<=>37x+7x=-5-28
<=>44x=-33
<=>x=-3/4
6)đề
<=>x+1=1/x+2
=>(x+1)(x+2)=1
<=>x^2+2x+1+2-1=0
<=>(x+1)^2+1=0
<=>(x+1)^2=-1(vl)