Question 1126375
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A farmer has 90 meters of fencing and would like to use the fencing to create a rectangular garden in the middle of an open field. 
Let l represent the varying length of the rectangular garden (in meters) and let A
represent the area of the garden (in square meters).
A)Write a formula that expresses A in terms of l.
B)What is the maximum area of the garden?
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Use "L" for "length", not "l".  
You can choose w for width.


90 meters of fence material.
If all 90 meters will be used, then   {{{2L+2w=90}}.
Same as  {{{L+w=45}}}.


If A is variable for area, then {{{A=wL}}}.

Substitute for w.
{{{highlight(A=L(45-L))}}}
OR
{{{highlight(A=45L-L^2)}}}


Maximum area will be for a square shape.  Each dimension of the rectangular (SQUARE) garden is  22.5 meters.