The rectangular field is 2100 square feet the length is 50 feet the field is divided into 3 rectangles x ft, 3x ft and 2x ft write and solve the equation

Rectangle area = length * width
2100                = 50       * w
width = 2100/50 = 42 feet
the three rectangles suppose there widths are as :x ft,3x ft , 2x ft = 42ft
x + 3x + 2x = 42
6x = 42 > x = 42/6 = 7 ft
x = 7ft> 2x = 14ft > 3x = 21 ft
now the first rectangle will be of dimensions of 7 ft by 50 ft > 350 ft2
        the second rectangle will be of                  14 ft by 50 ft > 700 ft2
        the third rectangle will be of                       21 ft by 50 ft > 1050 ft2  
so the total  Field    area is : 350 +700 +1050 = 2100 ft2