The rectangular plot of land is to be enclosed utilizing two types of fencing. Two opposite sides will have heavy duty fencing costing $3/ft, where as other two sides will have standard fencing costing $2/ft. Total of $600 is available for fencing. Let x be length of every side with heavy duty fencing, and let y be length of every side with standard fencing.
a.) State y in terms of x.
b.) Determine the formula for area A of rectangular plot in terms of x.
c.) Determine largest area which can be enclosed?