方程组:x-y=1,x+2y=3a的解满足:x>0,y

问题描述:

方程组:x-y=1,x+2y=3a的解满足:x>0,y

数学人气:992 ℃时间:2020-09-10 17:52:37
优质解答
x-y=1(1)
x+2y=3a(2)
(2)-(1):
3y=3a-1
y=a-1/3
x=y+1=a+2/3
x>0,ya+2/3>0
a-1/3-2/3

x-y=1(1)
x+2y=3a(2)
(2)-(1):
3y=3a-1
y=a-1/3
x=y+1=a+2/3
x>0,ya+2/3>0
a-1/3-2/3