Chapter 4: Problem 16
Find each product. $$ x(2 x+5)^{2} $$
Short Answer
Expert verified
The product is \(4x^3 + 20x^2 + 25x\).
Step by step solution
01
- Recognize the Given Expression
The given expression to find the product is \( x(2x + 5)^2 \). This is a polynomial multiplication problem.
02
- Apply the Binomial Theorem
Use the binomial theorem to expand \((2x + 5)^2\). According to the binomial theorem, \((a + b)^2 = a^2 + 2ab + b^2\). Here, let \(a = 2x\) and \(b = 5\).
03
- Expand the Binomial
Expand \((2x + 5)^2\): \[(2x + 5)^2 = (2x)^2 + 2(2x)(5) + (5)^2\] Calculate these individually: \[(2x)^2 = 4x^2\] \[2(2x)(5) = 20x\] \[5^2 = 25\] Now combine them: \[4x^2 + 20x + 25\]
04
- Distribute the Monomial
Now multiply the expanded binomial \(4x^2 + 20x + 25\) by the monomial \(x\). This means multiplying each term in the polynomial by \(x\): \[x \times (4x^2 + 20x + 25)\] This gives: \[4x^3 + 20x^2 + 25x\]
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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 fundamental concept in algebra that provides a way to expand expressions that are raised to a power. For example, \( (a + b)^n \) can be expanded using the theorem, which states that:
\[ (a + b)^n = \binom{n}{0}a^n + \binom{n}{1}a^{n-1}b + \binom{n}{2}a^{n-2}b^2 + ... + \binom{n}{n}b^n \]
This can look complex, but it's straightforward with practice.
For instance, if we have \( (2x + 5)^2 \), we can expand it as follows:
\[ 4x^2 + 20x + 25 \]
With understanding the binomial theorem, expanding polynomials becomes much easier!
\[ (a + b)^n = \binom{n}{0}a^n + \binom{n}{1}a^{n-1}b + \binom{n}{2}a^{n-2}b^2 + ... + \binom{n}{n}b^n \]
This can look complex, but it's straightforward with practice.
For instance, if we have \( (2x + 5)^2 \), we can expand it as follows:
- Identify 'a' and 'b': Here, 'a' is 2x and 'b' is 5.
- Apply the General Formula: According to the binomial theorem,
\[ (2x + 5)^2 = (2x)^2 + 2(2x)(5) + (5)^2 \] - Calculate:
\[ (2x)^2 = 4x^2 \]
\[ 2(2x)(5) = 20x \]
\[ (5)^2 = 25 \]
\[ 4x^2 + 20x + 25 \]
With understanding the binomial theorem, expanding polynomials becomes much easier!
polynomial expansion
Polynomial expansion is a process used in algebra to simplify expressions where terms consist of variables raised to a power. When working with polynomial expressions like \( (2x + 5)^2 \), the goal is to 'expand' this into a simple expression.
Here is how we do this:
Here is how we do this:
- Start with the Binomial: Look at the polynomial we need to expand, in this case \( (2x + 5)^2 \).
- Apply the Binomial Theorem: Expand using the theorem: \[ (2x + 5)^2 = (2x)^2 + 2(2x)(5) + (5)^2 \]
- Calculate Individual Terms: Calculate each term separately:
\[ (2x)^2 = 4x^2 \]
\[ 2(2x)(5) = 20x \]
\[ (5)^2 = 25 \] - Combine Terms: Add up the calculated terms to get the expanded polynomial:
\[ 4x^2 + 20x + 25 \]
distributive property
The distributive property is essential when multiplying polynomials. It states that multiplying a number by a sum is the same as multiplying the number by each term in the sum and then adding the products.
Mathematically, this is expressed as:
\[ a(b + c) = ab + ac \]
This principle helps break down complex multiplications like \( x(4x^2 + 20x + 25) \). Here's how you apply it step-by-step:
Mathematically, this is expressed as:
\[ a(b + c) = ab + ac \]
This principle helps break down complex multiplications like \( x(4x^2 + 20x + 25) \). Here's how you apply it step-by-step:
- Identify the Monomial and Polynomial: In our example, the monomial is 'x' and the polynomial is \( (4x^2 + 20x + 25) \).
- Distribute the Monomial: Multiply 'x' by each term in the polynomial:
\[ x \times 4x^2 = 4x^3 \]
\[ x \times 20x = 20x^2 \]
\[ x \times 25 = 25x \] - Combine Results: Put together the products to get:
\[ 4x^3 + 20x^2 + 25x \]