(3x-2y)^4

2 min read Jun 16, 2024
(3x-2y)^4

Expanding (3x-2y)^4 using the Binomial Theorem

The expression (3x-2y)^4 can be expanded using the Binomial Theorem, which states:

(a + b)^n = ∑_(k=0)^n (n choose k) a^(n-k) b^k

where (n choose k) is the binomial coefficient, calculated as:

(n choose k) = n! / (k! * (n-k)!)

Let's break down the expansion of (3x - 2y)^4 step-by-step:

1. Identify 'a' and 'b'

In our expression, a = 3x and b = -2y.

2. Determine the value of 'n'

Here, n = 4.

3. Apply the Binomial Theorem formula

Expanding the expression using the formula:

(3x - 2y)^4 = (4 choose 0) (3x)^4 (-2y)^0 + (4 choose 1) (3x)^3 (-2y)^1 + (4 choose 2) (3x)^2 (-2y)^2 + (4 choose 3) (3x)^1 (-2y)^3 + (4 choose 4) (3x)^0 (-2y)^4

4. Calculate the binomial coefficients

  • (4 choose 0) = 4! / (0! * 4!) = 1
  • (4 choose 1) = 4! / (1! * 3!) = 4
  • (4 choose 2) = 4! / (2! * 2!) = 6
  • (4 choose 3) = 4! / (3! * 1!) = 4
  • (4 choose 4) = 4! / (4! * 0!) = 1

5. Simplify the expression

Substituting the coefficients and simplifying:

(3x - 2y)^4 = 1(81x^4) + 4(27x^3)(-2y) + 6(9x^2)(4y^2) + 4(3x)(-8y^3) + 1(16y^4)

Finally, we get:

(3x - 2y)^4 = 81x^4 - 216x^3y + 216x^2y^2 - 96xy^3 + 16y^4

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