Question

The length of a rectangle is 4 units less than twice the width. What is the width if the area of the rectangle is 160 square units

Answer 1

check the picture below.

notice, the value cannot be a negative value, since it's a length unit, thus is not -8.

Answer 2

Let w be the width of the rectangle. Then the length would be 2w-4. So:
w(2w-4)=160
2w²-4w-160=0
w²-2w-80=0
(w+8)(w-10)=0
w=-8 or 10
The width is 10
☺☺☺☺