Let's assume
length =l
width =w
we are given
the width of a rectangle is 7 feet less than its length
so, we get
[tex] w=l-7 [/tex]
now, we know that
area = length*width
[tex] A=l*w [/tex]
now, we can plug w
[tex] A=l*(l-7) [/tex]
we have
Area=170
[tex] 170=l*(l-7) [/tex]
[tex] l^2-7l-170=0 [/tex]
now, we can factor it
[tex] (l-17)(l+10)=0 [/tex]
now, we can solve for l
[tex] (l-17)=0 [/tex]
[tex] length=17 feet [/tex]
now, we can find width
[tex] w=17-7 [/tex]
[tex] width=10 feet [/tex]
so, dimensions are
[tex] length=17 feet [/tex]
[tex] width=10 feet [/tex]...............Answer