Question

The perimeter of a rectangle wooden deck is 90 feet. The decks length, l, is 5 feet less than 4 times it's width, w. What's the system of linear equations that can be used to determine the dimensions, in feet, of the wooden deck?

Answer 1

P=2(l)+2(w)

90=2(4w-5)+2(w)
90= (8w-10)+2w
90=10w-10

10+90=10w-10+10
100=10w
w=10

90=2(4[10]-5)+2(10)
90=2(40-5)+2(10)
90=2(35)+20
90=70+20
90=90