Question 945916

A rectangle has a length of {{{L=3(x+y)}}} and a width of {{{W=3(x-y)}}} 

the perimeter of the rectangle is:{{{P=2L+2W}}}

{{{P=2*3(x+y)+2*3(x-y)}}}

{{{P=6(x+y)+6(x-y)}}}

{{{P=6x+6y+6x-6y}}}

{{{P=6x+cross(6y)+6x-cross(6y)}}}

{{{P=6x+6x}}}

{{{P=12x}}}