F.2 MATHS!

18(5m-2)^2-2(m+1)^2
=2[9(5m-2)^2-(m+1)^2]
=2{[3(5m-2)]^2-(m+1)^2}
=2{[3(5m-2)+(m+1)][3(5m-2)-(m+1)]}
=2(15m-6+m+1)(15m-6-m+1)
=2(16m-5)(14m-5)

2006-11-01 01:42:38 補充：
18(5m-2)^2-2(m+1)^2=2[9(5m-2)^2-(m+1)^2]=2{[3(5m-2)]^2-(m+1)^2}=2{[3(5m-2)+(m+1)][3(5m-2)-(m+1)]}=2(15m-6+m+1)(15m-6-m-1)=2(16m-5)(14m-7)=14(16m-5)(2m-1)梳~因計得太快，所以有些計錯了！今次這個就沒錯了！

18(5m-2)^2-2(m+1)^2

=18(25m^2-20m+4)-2(m^2+2m+1)

=450m^2-360m+72-2m^2-4m-2

=448m^2-364m+70

18(5m-2)^2-2(m+1)^2
=18(25m^2-4)-2(m^2+2)
=450m^2-72-2m^2-4
=448m^2-76

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= 18(25m^2 - 20m +4) - 2 (m^2 +2m +1)
= 450 m^2 - 360m + 72 - 2m^2 -4m -2
= 448m^2 -364m +70

2006-11-01 01:39:00 補充：
= 14 (16m-5) (2m-1)