You are building a rectangular deck. the area of the deck should be 250 ft.² . you want the lengths of the deck to be 5 feet longer than twice its width. what should the dimensions of the deck be?

Et the width be x 
"the length of the deck to be 5 ft longer than twice its width" --- >length = 2x+5 

then 
x(2x+5) = 250 
2x^2 + 5x - 250 = 0 
(x - 10)(2x + 25) = 0 
x = 10 or x is a negative, which makes no sense 

width = 10 
length = 25 

check: 
is the length 5 more than twice the width ?? yes 
is the area 250 ? yes

(-14+3/2b) - (1+8/2b) = -5 -5/2b(-10+b) + (7b-5) = 8b-15(7/2b-3) - (8+6b) = -5/2b-11(5+2b) + (2b+3/2) = 4b+ 13/2