The binomial expansion:

a = 2y, b = 4 x^3, n = 4
( x )^3k = x^ 9
k = 3


Answer: the coefficient is
512.
When using factoring by grouping, the replacement terms will both have the same sign of the original middle term. If the last term is negative, then the signs of the factors will have one of each sign with the “stronger” number (the larger absolute value) matching the middle term. hope this helps
Answer: 3/1000 as a decimal is 0.003.
Explanation;
3/10 = 0.3
0.3/10 = 0.03
0.03/10 = 0.003