Answer :

[tex]3x^2+14x-5=0\\\\3x^2+15x-x-5=0\\\\3x(x+5)-1(x+5)=0\\\\(x+5)(3x-1)=0\iff x+5=0\ or\ 3x-1=0\\\\x=-5\ or\ 3x=1\\\\\boxed{x=-5\ or\ x=\frac{1}{3}}[/tex]