Chapter 10 Counting Methods and Probability - 10.2 Use Combinations and Binomial Theorem - 10.2 Exercises - Skill Practice - Page 695: 35

Option A

We know from the Binomial Theorem (page 693) that we can expand the given expression without multiplying it out. Doing this, we obtain: $$x^7-21x^6+189x^5-945x^4+2835x^3-5103x^2+5103x-2187$$ Thus, the given coefficient is -945.