<PRE><B>Question 1191079</B>
A square plot of land is covered with cement costing $8/m^2 and a fence surrounding it costs $10/m. If the total cost is $8400, find the area of the plot
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side length = s
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Cost = 8s^2 + 4*10s = 8400
8s^2 + 40s - 8400 = 0
s^2 + 5s - 1050 = 0
(s-30)*(s+35) = 0
s = 30 meters
Area = 900 sq meters</PRE>