the length of a deck is 5 less than twice the width with a perimeter of 62 feet. what is the width of the deck rounded to the nearest tenth

Let ℓ equal length, w equal width, and P equal perimeter.

Use the formula 2ℓ + 2w = P.

ℓ = 2w - 5

2ℓ + 2w = 62

Substitute what you do know for what you don't, and solve.

2 (2w-5) + 2w = 62

4w - 10 + 2w = 62

6w - 10 = 62

6w = 72

w = (72/6)

w = 12

The answer is 12 feet.