Area = length * width
length = (2 * width) - 1
[tex] 10 = l*w\\
10=(2w-1)*w\\
10=2w^{2}-w\\
2w^{2}-w-10=0\\
(2w-5)(w+2)=0\\\\
2w-5=0\\
2w=5\\
w=\frac{5}{2}=2.5\\
w+2=0\\
w=-2 [/tex]
Since length cannot be negative, w = -2 is not a solution. Thus, [tex] \frac{5}{2}~ft[/tex] is your width.
Since length = 2 * width - 1, plug in width:
[tex] l=2(\frac{5}{2})-1\\
l=5-1\\
l=4~ft[/tex]
