So D x= 5 is the right answer
C- Commutative property.
Explanation: The numbers are flipped around, but still give you the same answer!
One way is to just expand it by using binomial theorem
or to use pascal's triangle
ok so
to find the nth term of a binomial, (a-b). where the binomial is to the r power you do
n-1=k
rCk times

and rCk=

so
4th term
4-1=3
6 is exponent
6C3

=

=

=

the 4th term is