Question 628729
You are going in the right direction, good.
Let us define x as the length of the rectangle and y as the width of the rectangle.

now,
{{{ 2x + 2y = 42}}} ----because this is the perimeter of the rectangle

and x = y + 7 since length is 7feet longer than the width.

Let us substitute x in the above eq which gives us,
{{{ 2(y+7) + 2y = 42}}}
which on solving gives us,

2y+ 14 + 2y = 42 => y = 7 which is the width
and x = 14 which is the length