Answer :
Let l be the length, and l-7 be the width. Then:
l(l-7)=170
l²-7l-170=0
(l-17)(l+10)=0
l=17 or -10
The length is 17 ft, the width is 10 ft
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l(l-7)=170
l²-7l-170=0
(l-17)(l+10)=0
l=17 or -10
The length is 17 ft, the width is 10 ft
☺☺☺☺