①式两边同乘以6 得 30x +42y = 41.(3)
②式两边分别同乘以（6* 15）和（6* 14）得30x+ 45y= 45.(4)
28x+ 42y= 42.(5)
(4) - (3)得 3y = 4 则 y = 4/3
(3) - (5)得 2x = - 1 则 x = - 1/2