(5-x)(6-x)(4-x)-4(4-x)-4(6-x)
=(5-x)(6-x)(4-x)-4[(4-x)+(6-x)]
=(5-x)(6-x)(4-x)-4(10-2x)
=(5-x)(6-x)(4-x)-8(5-x)
=(5-x)[(6-x)(4-x)-8]
=(5-x)(x²-10x+16)
=-(x-5)(x-2)(x-8)
(5-x)(6-x)(4-x)-4(4-x)-4(6-x)
=(5-x)(6-x)(4-x)-4[(4-x)+(6-x)]
=(5-x)(6-x)(4-x)-4(10-2x)
=(5-x)(6-x)(4-x)-8(5-x)
=(5-x)[(6-x)(4-x)-8]
=(5-x)(x²-10x+16)
=-(x-5)(x-2)(x-8)