a rectangular gardan has a length of xm and a breadth of ym. It has an area of 20m and a perimeter of 18m determine the velue of x and y

2x + 2y = 18

x + y = 9
y = 9-x

also , xy = 20
x(9-x) = 20
9x - x^2 - 20 = 0
x^2 - 9x + 20 = 0
(x-4)(x-5) = 0
x = 4 or x = 5

if x = 4, then y = 5
if x = 5, then y = 4

you have symmetric answers,
the field is 4 m by 5 m