Question 598603
First things first, write out two equations for your problem.

1: The perimeter equals 2 lengths + 2 widths. The perimeter equals 44 inches.
{{{2l + 2W = P}}}
{{{2L + 2W = 44}}}.

2: the width is 6 inches. {{{W=6}}}.

Now combine the equations and simplify.
{{{2L + 2W = 44}}}
{{{2L + 2(6) = 44}}}
{{{2L + 12 = 44}}}
 
Of course, you want to find the length. So we merely get L alone on one side fo the equation - its called isolating the variable. REMEMBER: whatever you do to one side of the equation, you MUST do to the other side.

{{{2L + 12 = 44}}}
{{{2L + 12 - 12 = 44 - 12}}}
{{{2L = 44 - 12}}}
{{{2L = 32}}}

Dont forget to divide by two to get the length of one side! 

{{{2L/2 = 32/2}}}
{{{L = 16}}}

The length is 16 inches. 
I hope this helps you, and good luck in your math!