Chapter 4: Problem 46
Find each product. $$ (m-5)^{3} $$
Short Answer
Expert verified
\( (m-5)^3 = m^3 - 15m^2 + 75m - 125 \)
Step by step solution
01
- Understand the Problem
The expression \( (m-5)^{3} \) represents a cubic binomial which needs to be expanded.
02
- Use the Binomial Theorem
The Binomial Theorem states that \[ (a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k \]. For this problem let \( a = m \), \( b = -5 \), and \( n = 3 \).
03
- Expand the Binomial
Using the Binomial Theorem: \( (m-5)^{3} = \sum_{k=0}^{3} \binom{3}{k} m^{3-k} (-5)^k \).
04
- Calculate Each Term
Calculate each term separately: \ \ \ \ when \( k = 0 \): \ \ \ \ \( \binom{3}{0} m^{3-0} (-5)^0 = 1 \cdot m^3 \cdot 1 = m^3 \) \ \ \ \ \ when \( k = 1 \): \ \ \ \ \( \binom{3}{1} m^{3-1} (-5)^1 = 3 \cdot m^2 \cdot (-5) = -15m^2 \) \ \ \ \ \ when \( k = 2 \): \ \ \ \ \( \binom{3}{2} m^{3-2} (-5)^2 = 3 \cdot m \cdot 25 = 75m \) \ \ \ \ \ when \( k = 3 \): \ \ \ \ \( \binom{3}{3} m^{3-3} (-5)^3 = 1 \cdot 1 \cdot (-125) = -125 \)
05
- Combine the Terms
Combine all the terms to get the expanded form: \ \ \( (m-5)^3 = m^3 - 15m^2 + 75m - 125 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Binomial Theorem
The Binomial Theorem is a powerful tool in algebra. It allows us to expand expressions of the form \( (a+b)^n \). This theorem is particularly useful when dealing with high powers of binomials. Here's the general formula:
\[ (a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k \]
In this formula, \( \binom{n}{k} \) represents the binomial coefficient, which can be calculated using combinations. Essentially, it tells you how many ways you can choose \( k \) elements from \( n \) elements.
For the example \( (m-5)^3 \), the variables are \( a = m, \) \( b = -5, \) and \( n = 3 \). Applying the Binomial Theorem helps break down the binomial to individual terms which are easier to compute.
\[ (a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k \]
In this formula, \( \binom{n}{k} \) represents the binomial coefficient, which can be calculated using combinations. Essentially, it tells you how many ways you can choose \( k \) elements from \( n \) elements.
For the example \( (m-5)^3 \), the variables are \( a = m, \) \( b = -5, \) and \( n = 3 \). Applying the Binomial Theorem helps break down the binomial to individual terms which are easier to compute.
Polynomial Expansion
Polynomial expansion involves transforming expressions like \( (m-5)^3 \) into a sum of simpler terms. This makes calculations and understanding the behavior of the polynomial easier.
When we use the Binomial Theorem on \( (m-5)^3 \), we follow these steps:
In this case, we get:
\[ (m-5)^3 = m^3 - 15m^2 + 75m - 125 \]
By expanding a polynomial, we express it in a form that clearly shows each term's contribution. This is helpful in finding roots, factoring, and integrating or differentiating the polynomial.
When we use the Binomial Theorem on \( (m-5)^3 \), we follow these steps:
- Identify \( a \), \( b \), and \( n \).
- Compute each term using the binomial coefficients and the powers of \( a \) and \( b \).
- Combine all the terms to get the expanded polynomial.
In this case, we get:
\[ (m-5)^3 = m^3 - 15m^2 + 75m - 125 \]
By expanding a polynomial, we express it in a form that clearly shows each term's contribution. This is helpful in finding roots, factoring, and integrating or differentiating the polynomial.
Cubic Binomial
A cubic binomial is a binomial expression raised to the power of three, like \( (m-5)^3 \). These types of expressions are common in algebra and have specific properties due to the cubic term.
When expanding a cubic binomial, you'll end up with four terms because \( n = 3 \) in the Binomial Theorem. Each term of the cubic binomial comes from applying the binomial coefficients and the respective powers of \( a \) and \( b \).
For \( (m-5)^3, \) we calculate each term as follows:
Combining these terms gives us the expanded form: \[ (m-5)^3 = m^3 - 15m^2 + 75m - 125 \]. Understanding how to handle cubic binomials is essential, as it lays the foundation for more complex polynomial expansions.
When expanding a cubic binomial, you'll end up with four terms because \( n = 3 \) in the Binomial Theorem. Each term of the cubic binomial comes from applying the binomial coefficients and the respective powers of \( a \) and \( b \).
For \( (m-5)^3, \) we calculate each term as follows:
- \( k = 0 \): \( \binom{3}{0} m^{3-0} (-5)^0 = m^3 \)
- \( k = 1 \): \( \binom{3}{1} m^{3-1} (-5)^1 = -15m^2 \)
- \( k = 2 \): \( \binom{3}{2} m^{3-2} (-5)^2 = 75m \)
- \( k = 3 \): \( \binom{3}{3} m^{3-3} (-5)^3 = -125 \)
Combining these terms gives us the expanded form: \[ (m-5)^3 = m^3 - 15m^2 + 75m - 125 \]. Understanding how to handle cubic binomials is essential, as it lays the foundation for more complex polynomial expansions.