4（x+y)-5(x-y)=2既 9y-x=2 再和你算得 5x+y=36 联立得 x=7 y=1
(x+y)/2+(x-y)/3=6两边乘63(x+y)+2(x-y)=363x+3y+2x-2y=365x+y=36 (1)4(x+y)-5(x-y)=24x+4y-5x+5y=2-x+9y=2所以x-9y=-2 (2)
