Question

已知方程组3x+2y=m+1，2x+y=m-1，问m为何值时，x大于y？

Answer 1

3x+2y=m+1 (1)
2x+y=m-1 (2)
(1)- (2)得
x+y=2
2x+2y=4 (3)
(1)- (3)得
x=m-3
(3)-(2)得
y=5-m
若x>y,则
m-3>5-m
m>4

Answer 2

3x+2y=m+1 (1)
2x+y=m-1 (2)
(2)×5-(1)×3
10x+5y-9x-6y=5m-5-3m-3
m-y=2m-8
x>y则x-y>0
所以2m-8>0
2m>8
m>4