若方程组2X+3Y=2K-1,3X+2Y=K+1的解满足X>Y>0,则K的取值范围是
问题描述:
若方程组2X+3Y=2K-1,3X+2Y=K+1的解满足X>Y>0,则K的取值范围是
答
2X+3Y=2K-1,3X+2Y=K+1
相加5X+5Y=3K
X+Y=3K/5
2X+2Y=6K/5
2X+3Y=2K-1
所以Y=2K-1-6K/5=4K/5-1
X=3K/5-Y=1-K/5
X〉Y〉0
1-K/5>4K/5-1>0
4K/5-1>0
4K/5>1
K>5/4
1-K/5>4K/5-1
K所以5/4