Question

Help.
Use the foil method to find the product.
(3x^8-9)(x^9-7)
my answer 3x^17-9x^9-21x^8+63

Answer 1

you are correct.
=3x^17 - 21x^8 - 9x^9 +63

Answer 2

thanks

Answer 3

there is no 'foil' method that you have to concern your self with; it is just plain and simple multiplications:

3x^8 -9
x^9 -7
------------
3x^17 -9x^9
-21x^8 +63
----------------------
\(3x^{17} -9x^9 -21x^8 +63\)