Question

已知直线2x+y=3m与直线x+3y=2m-3的交点在第四象限,求m的范围

Answer 1

2x+y=3m

x+3y=2m-3

x = (3 + 7 m)/5

y = (-6 + m)/5

第四象限, x>0, y 0

-6 + m < 0

-3/7 < m < 6