已知(x-y-1)方+根号2 x+y+4=0,求x-3y的算术平方根
问题描述:
已知(x-y-1)方+根号2 x+y+4=0,求x-3y的算术平方根
答
(x-y-1)方+根号2 x+y+4=0
x-y-1=0
x-y=1
2x+y+4=0
2x+y=-4
3x=-3
x=-1
y=-2
x-3y=-1+6=5
x-3y的算术平方根=根号5