2x-y=2a,(1)
x+3y=a-1 (2)
(1) * 3得
6x - 3y = 6a (3)
(2)+(3)得
7x = 7a -1
x = a - 1/7
代入(1)得
y = -2/7
又 x > y
a - 1/7 > - 2/7
a > - 1/7
2x-y=2a,(1)
x+3y=a-1 (2)
(1) * 3得
6x - 3y = 6a (3)
(2)+(3)得
7x = 7a -1
x = a - 1/7
代入(1)得
y = -2/7
又 x > y
a - 1/7 > - 2/7
a > - 1/7