Math Problem Statement

Expand and simplify the binomial: (3a - 2b)^5

Solution

To expand and simplify the binomial (3a2b)5(3a - 2b)^5, we use the Binomial Theorem, which states:

(x+y)n=k=0n(nk)xnkyk(x + y)^n = \sum_{k=0}^n \binom{n}{k} x^{n-k} y^k

Here:

  • n=5n = 5 (the power),
  • x=3ax = 3a and y=2by = -2b.

The general term is given as:

Tk=(5k)(3a)5k(2b)kT_k = \binom{5}{k} (3a)^{5-k} (-2b)^k

Now we calculate each term by substituting values of kk from 0 to 5:


Step-by-step Expansion:

  1. For k=0k = 0: T0=(50)(3a)5(2b)0=1243a51=243a5T_0 = \binom{5}{0} (3a)^5 (-2b)^0 = 1 \cdot 243a^5 \cdot 1 = 243a^5

  2. For k=1k = 1: T1=(51)(3a)4(2b)1=581a4(2b)=810a4bT_1 = \binom{5}{1} (3a)^4 (-2b)^1 = 5 \cdot 81a^4 \cdot (-2b) = -810a^4b

  3. For k=2k = 2: T2=(52)(3a)3(2b)2=1027a34b2=1080a3b2T_2 = \binom{5}{2} (3a)^3 (-2b)^2 = 10 \cdot 27a^3 \cdot 4b^2 = 1080a^3b^2

  4. For k=3k = 3: T3=(53)(3a)2(2b)3=109a2(8b3)=720a2b3T_3 = \binom{5}{3} (3a)^2 (-2b)^3 = 10 \cdot 9a^2 \cdot (-8b^3) = -720a^2b^3

  5. For k=4k = 4: T4=(54)(3a)1(2b)4=53a16b4=240ab4T_4 = \binom{5}{4} (3a)^1 (-2b)^4 = 5 \cdot 3a \cdot 16b^4 = 240ab^4

  6. For k=5k = 5: T5=(55)(3a)0(2b)5=11(32b5)=32b5T_5 = \binom{5}{5} (3a)^0 (-2b)^5 = 1 \cdot 1 \cdot (-32b^5) = -32b^5


Combine All Terms:

Adding all terms together, we get:

(3a2b)5=243a5810a4b+1080a3b2720a2b3+240ab432b5(3a - 2b)^5 = 243a^5 - 810a^4b + 1080a^3b^2 - 720a^2b^3 + 240ab^4 - 32b^5


Final Answer:

243a5810a4b+1080a3b2720a2b3+240ab432b5\boxed{243a^5 - 810a^4b + 1080a^3b^2 - 720a^2b^3 + 240ab^4 - 32b^5}

Let me know if you need further clarification or steps explained!


Related Questions:

  1. How does the binomial theorem work for negative terms?
  2. Can you expand (x+y)6(x + y)^6 step-by-step?
  3. How do you find the general term of a binomial expansion?
  4. What is Pascal’s Triangle and how is it related to binomial coefficients?
  5. How can the binomial theorem be applied to approximations?

Tip:

The binomial theorem is a quick way to expand powers of binomials without direct multiplication.

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Math Problem Analysis

Mathematical Concepts

Algebra
Binomial Expansion
Exponents

Formulas

Binomial Theorem: (x + y)^n = Σ [C(n, k) * x^(n-k) * y^k]

Theorems

Binomial Theorem

Suitable Grade Level

Grades 10-12