Mamadou

The output is eight less than the input

Area A=x.y The perimeter of a rectangle is 2x+y= 280 solving for y give you,m y=280-2x, y is greater to zero. A=x*y substituting y in the area equation give you A=x(280-2x.)=280x-2x^2 The area is maximized when A'=0 so first find the derivative of A A'=28...