+980 The area of a rectangle is 80 sq ft. If the width is increased by 1 foot and the length is decreased by 1 foot, the new rectangle has area 90 sq ft. What is the perimeter of the original rectangle, in feet?
+47 S1∗S2=80
[S1+1]∗[S2−1]=90
S1=80S2
[80S2+1]∗[S2−1]=90
[80+S2S2]∗[S2−11]=90
80S2−80+(S2)2−S2S2=90
80S2−80+(S2)2−S2=90S2
80S2−80+(S2)2−S2−90S2=0
−80+(S2)2−11S2=0
(S2)2−11S2−80=0
S2=16
S1=5
p=42
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