第二个式子应为【(3x-2y)分之27 - (2x-3y)分之2 = 1 】
11/(2x-3y) +18/(3x-2y) = 13 ...(1)
27/(3x-2y) - 2/(2x-3y) = 1 ...(2)
令2x-3y = s,3x-2y = t
11/s + 18/t = 13 ...(3)
27/t - 2/s = 1 ...(4)
(3)*3-(4)*2：
(33+4)/s = 39-2
s=1
11/1+18/t=13
t=9
2x-3y = 1 ...(5)
3x-2y = 9 ...(6)
(6)*3-(5)*2:
9x-4x=27-2
x=5
y=(2x-1)/3=3