In the expansion of (3x - 2)^4, what is the coefficient of x^1?

Practice Questions

Q1
In the expansion of (3x - 2)^4, what is the coefficient of x^1?
  1. -48
  2. -72
  3. 72
  4. 48

Questions & Step-by-Step Solutions

In the expansion of (3x - 2)^4, what is the coefficient of x^1?
  • Step 1: Identify the expression to expand, which is (3x - 2)^4.
  • Step 2: Recognize that we need to find the coefficient of x^1 in the expansion.
  • Step 3: Use the Binomial Theorem, which states that (a + b)^n = Σ (nCk * a^(n-k) * b^k) for k = 0 to n.
  • Step 4: In our case, a = 3x, b = -2, and n = 4.
  • Step 5: We want the term where the power of x is 1, which means we need (3x)^1 and (-2)^(4-1) = (-2)^3.
  • Step 6: To find this term, we need to calculate the binomial coefficient for k = 3 (since we want x^1, which corresponds to k = n - 1).
  • Step 7: Calculate the binomial coefficient: 4C3 = 4! / (3! * (4-3)!) = 4.
  • Step 8: Now calculate the term: 4C3 * (3x)^1 * (-2)^3.
  • Step 9: Substitute the values: 4 * (3x) * (-8) (since (-2)^3 = -8).
  • Step 10: Simplify: 4 * 3 * (-8) = -96.
  • Step 11: The coefficient of x^1 in the expansion is -96.
No concepts available.
Soulshift Feedback ×

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

Not likely Very likely