解:﹙x-1﹚﹙x-3﹚-5
=x²-4x-2
=﹙x-2﹚²-3
=﹙x-2-√3﹚﹙x-2+√3﹚.
原式=x²-4x+3-5
=x²-4x+4-6
=(x-2)²-6
=(x-2+√6)(x-2-√6)
(x-1)(x-3)-5
=x^2-4x-2
=(x-2)^2-6
=(x-2+√6)(x-2-√6)
( x - 1 )( x + 3 ) - 5
= x" + 3x - x - 3 - 5
= x" + 2x - 8
= x" + 4x - 2x - 8
= x( x + 4 ) - 2( x + 4 )
= ( x - 2 )( x + 4 )