The expression to be simplified is,
[tex]\frac{6}{6+12x}[/tex]
It can be written as:
[tex]\frac{6}{6+12x}=\frac{6}{6+6\times2x}[/tex]
Take the common factors outside from the right hand side of the above equation.
[tex]\frac{6}{6+12x}=\frac{6}{6(1+2x)}[/tex]
Cancel out the common factor 6 in the numerator and denominator of the fraction at the right hand side of the above equation.
[tex]\frac{6}{6+12x}=\frac{1}{(1+2x)}[/tex]
Therefore, the correct expression is,
[tex]\frac{6}{6+12x}=\frac{1}{(1+2x)}[/tex]
