In the expansion of (3x - 2)^5, what is the coefficient of x^3?

Practice Questions

Q1
In the expansion of (3x - 2)^5, what is the coefficient of x^3?
  1. -240
  2. -360
  3. 360
  4. 240

Questions & Step-by-Step Solutions

In the expansion of (3x - 2)^5, what is the coefficient of x^3?
  • Step 1: Identify the expression we are expanding, which is (3x - 2)^5.
  • Step 2: Recognize that we need to find the coefficient of x^3 in this expansion.
  • Step 3: Use the Binomial Theorem, which states that (a + b)^n = sum of (nCk * a^(n-k) * b^k) for k from 0 to n.
  • Step 4: In our case, a = 3x, b = -2, and n = 5.
  • Step 5: We want the term where the power of x is 3, which means we need (3x)^(3) and (-2)^(5-3) = (-2)^(2).
  • Step 6: To find the correct term, we need to calculate k, where k = 5 - 3 = 2.
  • Step 7: Calculate the binomial coefficient, which is 5C2. This is equal to 5! / (2! * (5-2)!) = 10.
  • Step 8: Calculate (3)^3, which is 27.
  • Step 9: Calculate (-2)^2, which is 4.
  • Step 10: Multiply these values together: 5C2 * (3)^3 * (-2)^2 = 10 * 27 * 4.
  • Step 11: Perform the multiplication: 10 * 27 = 270, and then 270 * 4 = 1080.
  • Step 12: Since we are looking for the coefficient of x^3, the final answer is 1080.
No concepts available.
Soulshift Feedback ×

On a scale of 0–10, how likely are you to recommend The Soulshift Academy?

Not likely Very likely