Reiny can you show me how to check this problem.

Question

5a^8-20a^7-25a^6

=5a^6(a^2-4a-5)

=5a^6(a^2-5a+a-5)

=5a^6(a(a-5)+1(a-5)

=5a^6(a-5)(a+1) (answer)

Answer 1

The GCF is always = to 0r less than the smallest coefficient:

GCF =< 5.

When a variable is involved, choose the
common variable of lowest degree(smallest exponent). All of this has been properly done.

Answer check:

Perform the multiplication; the product
should be identical to the expression
that was given.

5a^6(a-5)(a+1) =
(5a^7-25a^6)(a+1) =
5a^8 + 5a^7 - 25a^7 -25a^6 =
Combine like-terms:
5a^8 - 20a^7 - 25a^6.

Your answer is correct!