当a等于多少时,方程组﹛x+2y-6=0,x-y-9+3a=0的解满足x=y?

问题描述:

当a等于多少时,方程组﹛x+2y-6=0,x-y-9+3a=0的解满足x=y?

当x=y时
x-y-9+3a=0
3a=9
a=3