Problem 81 of 7
Identify the missing coefficient in expansion (x-3y)^3 = x^3 - 9x^2y + __xy^2 -.
Using a hint is okay. It just tells the trainer to give you a little more review.
Hidden until you reveal it.
use Pascal row or combination formula.
Hidden until you reveal it.
Use Pascal row or combination formula and include internal coefficients when present.
Enter your answer
Your answer is equivalent to the expected form.
Walkthrough
Full solution stays hidden until you ask for it.
1. Identify expansion power and term position.
2. Use Pascal or nCk for the base coefficient.
3. Multiply by any term coefficients raised to powers.
Use the worked steps, then substitute the final answer back into the original relationship to confirm it satisfies the prompt.
Using Pascal coefficient alone when binomial terms have coefficients.