Need help on #3 Please help me on my hw

Factor the left hand side:
[tex]\begin{gathered} \frac{6}{6}\cdot\frac{1}{1+2x}\ne\frac{1}{1+12x} \\ \frac{1}{1+2x}\ne\frac{1}{1+12x} \\ \end{gathered}[/tex][tex]1+12x\ne1+2x[/tex]Subtract 2x from both sides:
[tex]\begin{gathered} 1+12x-2x\ne1+2x-2x \\ 1+10x\ne1 \end{gathered}[/tex]Sutract 1 from both sides:
[tex]\begin{gathered} 1+10x-1\ne1-1 \\ 10x\ne0 \end{gathered}[/tex]Divide both sides by 10:
[tex]\begin{gathered} \frac{10x}{10}\ne\frac{0}{10} \\ x\ne0 \end{gathered}[/tex]Therefore, the equation is correct for every x different from 0.