Mathematical induction/factoring

[L²Cc]

[k(k+1)(k+2)(k+3) + 4(k+1)(k+2)(k+3)]/4
Please, factor this out...
What's the common factor? How did you get there? (ok i hope it doesn't require expanding the polynomials :p)
would it be easier if i substituted every (k+x) by a different variable, where (k+1) would equal to variable 'A', (k+2) = B, and so forth?

 

[drpizza]

Here's an example that may help:

(x+7)(x+8)(x+9) + (x+7)(x+11)(x+13)

Notice that both terms have (x+7) in common; so it's a common factor.

You can factor this as (x+7) * [(x+8)(x+9) + (x+11)(x+13)]

 

[L²Cc]

oh all right i see,
thanks a lot, take care!