a: f(x)=0
=>x=0 hoặc x-3,5=0
=>x=0; x=3,5
b: f(x)=0
=>x(x+1)(2x-3)=0
=>x=0; x=-1; x=3/2
c: f(x)=0
=>x(6-x)(3x+4)=0
=>x=0; x=6; x=-4/3
d: f(x)=0
=>5x(x+1)=0
=>x=0 hoặc x=-1
e: g(x)=0
=>2x(3x-1)=0
=>x=0 hoặc x=1/3
f: g(x)=0
=>3x(5x+1)=0
=>x=0 hoặc x=-1/5