a+b+|根號(hào)(c-1)-1|=4根號(hào)(a-2)+2根號(hào)(b+1)-4
(a-2)-4根號(hào)(a-2)+4+(b+1)-2根號(hào)(b+1)+1+|根號(hào)(c-1)-1|=0
[根號(hào)(a-2)-2]²+[根號(hào)(b+1)-1]²+|根號(hào)(c-1)-1|=0
因?yàn)榈仁降淖筮吤恳豁?xiàng)都是非負(fù)數(shù),所以要使結(jié)果等于0
必須有根號(hào)(a-2)-2=0,根號(hào)(b+1)-1=0,根號(hào)(c-1)-1=0
解得a=6,b=0,c=2
a+2b-3c=6+2×0-3×2=0