2a(a-2)与(a-1)(a-3)怎么比较大小

2a(a-2)与(a-1)(a-3)怎么比较大小
2a(a-2)与(a-1)(a-3)怎么比较大小

2a(a-2)与(a-1)(a-3)怎么比较大小
2a(a-2)-(a-1)(a-3)
=2a²-4a-a²+4a-3
=a²-3
所以
a√3,2a(a-2)>(a-1)(a-3)
a=-√3,a=√3,2a(a-2)=(a-1)(a-3)
-√3

2a(a-2)-(a-1)(a-3)
=2a²-4a-(a²-4a+3)
=-3<0
所以2a(a-2)<(a-1)(a-3)

2a(a-2)=2a*a-4a
(a-1)(a-3)=a*a-4a+3
2a(a-2)-(a-1)(a-3)=a*a+3>0
所以2a(a-2) >(a-1)(a-3)