Thread: please help me with this problem in Algebra

I can not grasp this area.. We are to factor by grouping and this problem states factor completely.. my textbook isn't much help at all. Can someone please help?


4a^2b-4a^2-4ab-4a

Originally Posted by planolerachel

I can not grasp this area.. We are to factor by grouping and this problem states factor completely.. my textbook isn't much help at all. Can someone please help?


4a^2b-4a^2-4ab-4a

Please re-check - there might be a typo. Could it be one of the following:

4a^2b + 4a^2 - 4ab - 4a

4a^2b - 4a^2 - 4ab + 4a

4a^2b - 4a^2 + 4ab - 4a

Sorry about that I did indeed type that incorrectlly..

4a^2b-4a^2-4ab+4a

Originally Posted by planolerachel

Sorry about that I did indeed type that incorrectlly..

4a^2b-4a^2-4ab+4a

= (4a^2b - 4a^2) - (4ab - 4a)

= 4a^2 (b - 1) - 4a (b - 1)

= (b - 1) (4a^2 - 4a)

= (b - 1) 4a (a - 1)

= 4a (b - 1) (a - 1).


Alternatively:

4a^2b-4a^2-4ab+4a

= 4a(ab - a - b + 1)

= 4a (a[b - 1] - [b - 1])

= 4a (a[b - 1] - 1[b - 1])

= 4a (a - 1)(b - 1).

I appreciate your help