A farmer has 900 m of fencing and wants to enclose a rectangular field bordering a river, with no fencing needed along the river. Let x represent the width of the field. Complete parts (a) through (d) below (a) Write an expression for the length of the Seld. Let the length of the field be the distance along the river (b) Find the area of the field. Let the length of the field be the distance along the river. (c) Find the value of x leading to the maximum area x= (Type an exact answer.) (d) Find the maximum area. The maximum area is