a: TH1: x>=1/3
=>9x-3=3x+5
=>6x=8
=>x=4/3(nhận)
TH2: x<1/3
=>-9x+3=3x+5
=>-12x=2
=>x=-1/6(nhận)
c: 3x(2x-9)-3(3+2x^2)=0
=>6x^2-27x-9-6x^2=0
=>27x+9=0
=>x=-1/3
b: (3x-1)^2-3(3x-2)=9(x+1)(x-3)
=>9x^2-6x+1-9x+6=9(x^2-2x-3)
=>9x^2-15x+7=9x^2-18x-27
=>-15x+7=-18x-27
=>3x=-34
=>x=-34/3


