(1)(a-x)(b-x)+(a-x)x*2+(b-x)x*2
(2)当x=1时
(a-x)(b-x)+(a-x)x*2+(b-x)x*2
= (a-1)(b-1))+(a-1)*1*2+(b-1)*1*2
= ab-b-a+1+2a-2+2b-2
= >.
(3)24*25*5=3000
(1)(a-x)(b-x)+(a-x)x*2+(b-x)x*2
(2)当x=1时
(a-x)(b-x)+(a-x)x*2+(b-x)x*2
= (a-1)(b-1))+(a-1)*1*2+(b-1)*1*2
= ab-b-a+1+2a-2+2b-2
= >.
(3)24*25*5=3000