maths問題!!!!!!!!help me

42ab-28b=
=a(42b-28b)
=14ab

5pq-45p
=(5p-45p)q
=-40pq

-24xy+40yz-16y
=16xy+z-16y
=x+z

4a(2次分)-18a
Because the is not has any like terms,so we cannot do any things.

Hope can help you
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2009-09-25 17:37:17 補充：
Factorize:

42ab-28b

=7b(6a-4)


5pq-45p

=5p(q-9)


-24xy+40yz-16y

=8y(-3x+5z-2)


4a(2次分)-18a

=2a(2a-9)

42ab-28b
7b(6a-4)

5pq-45p
5p(q-9)

-24xy+40yz-16y
8y(-3x+5z-2)

4a²-18a
2a(2a-9)

如有地方唔明~
唔怕再問~

42ab-28b= 7b(6a-4)

5pq-45p = 5p(q-9)

-24xy+40yz-16y= 8y(-3x+5z-2)

4a(2次分)-18a= 2a(2a-9)