Answer:
Lenght=50 feet.
Width=44 feet.
Explanation:
1. He wants the width of his new garden to be 6 less than the length, this can be expressed as following:

Where W is the width L is the length.
2. The perimeter of a rectangle can be calculated with:

3. You know the perimeter, therefore, you can substitute
into the equation of the perimeter and solve for the length:
(The length is 50 feet)
3. Then, the width is:

(The width is 44 feet)