Question 204715
the problem can be drawn like this:
{{{drawing( 300, 200, -1, 8, 2, 8,
rectangle( -1, 3, 3, 7 ),
rectangle( 3, 3, 7, 7 ),
locate(-0.8,5,x),
locate(3.2,5,x),
locate(7.2,5,x)
)
}}}


since the vertical side of the field is fenced x meters long each, then the 2 horizontal sides will be fenced (300 - 3x) meters long
so each horizontal side of the field is:
{{{(300 - 3x)/2}}} 
={{{150 - (3/2)x}}}
and the area of the field is:
Area = x(150 - 3/2 x)