Question 988596
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W=width; L=length=W+5cm
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LW=500cm^2 Substitute for L.
(W+5cm)(W)=500cm^2
W^2+5W=500
W^2+5W-500=0
(W+25)(W-20)=0
W+25=0 OR W-20=0
W=-25 OR W=20
Since -25 does not work:
ANSWER 1: The width is 20 cm.
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L=W+5cm=20cm+5cm=25cm
ANSWER 2: The length is 25 cm.
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CHECK: 
Area is 500cm^2:
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A=LW
500cm^2=(25cm)(20cm)
500cm^2=500cm^2