Answer & Step-by-step explanation:
Since you looking for the width and you are given the length and the area, then you will divide the area by the length.
(10x² + 5x) ÷ 5x
You can also turn this into a fraction so you can know what you are dividing.

So, your width is 2x + 1
1 lb = 16 oz
3 1/2 (or 3.5)lbs = 3.5(16) = 56 oz which equals : 2 lbs and 24 oz or 3 lbs and 8 oz or 1 lb and 40 oz