Question

1.当a为何值时,方程组｛x+y=a+1

Answer 1

1.x+y=a+1 (1)

2x-y=2a-4 (2)

(1)+(2),则x=a-1

将x的值代入(1),则y=2>0

x=a-1>0,故a>1

2.画出数轴

可见m