Chapter 5: Problem 48
Multiply. \((a+2)\left(a^{3}-3 a^{2}+7\right)\)
Short Answer
Expert verified
The product is \(a^4 - a^3 - 6a^2 + 7a + 14\).
Step by step solution
01
Apply the Distributive Property
To multiply \(a+2\) by \(a^3 - 3a^2 + 7\), we use the distributive property. This involves multiplying each term in \(a+2\) by each term in the polynomial \(a^3 - 3a^2 + 7\).
02
Distribute First Term (a)
First, distribute the \(a\) in \(a+2\) across each term of the polynomial: \[ a imes a^3 = a^4, \ a imes (-3a^2) = -3a^3, \ a imes 7 = 7a \] This gives us: \[ a^4 - 3a^3 + 7a \]
03
Distribute Second Term (2)
Now, distribute the \(2\) in \(a+2\) across each term of the polynomial: \[ 2 imes a^3 = 2a^3, \ 2 imes (-3a^2) = -6a^2, \ 2 imes 7 = 14 \] This gives us: \[ 2a^3 - 6a^2 + 14 \]
04
Combine Like Terms
Combine the results from Step 2 and Step 3: \[ (a^4 - 3a^3 + 7a) + (2a^3 - 6a^2 + 14) \] Combine like terms to simplify:\[ a^4 + (-3a^3 + 2a^3) - 6a^2 + 7a + 14 \] This simplifies to: \[ a^4 - a^3 - 6a^2 + 7a + 14 \]
05
Final Expression
The final result of multiplying \(a+2\) by \(a^3 - 3a^2 + 7\) is: \[ a^4 - a^3 - 6a^2 + 7a + 14 \]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Distributive Property of Multiplication
When multiplying algebraic expressions, the distributive property is a handy tool. It allows you to break down complex expressions into simpler pieces. The rule is simple: each term in one expression must be multiplied by each term in the other expression. This step-by-step approach ensures that no component is left behind.
In our exercise, we used the distributive property to multiply \((a+2)\) by \(a^3 - 3a^2 + 7\). Here's how it works:
In our exercise, we used the distributive property to multiply \((a+2)\) by \(a^3 - 3a^2 + 7\). Here's how it works:
- Multiply each term inside the parenthesis \((a+2)\) by every term in the other polynomial \(a^3 - 3a^2 + 7\).
- First, distribute \(a\) to each term: \(a \times a^3, a \times (-3a^2), a \times 7\).
- Next, distribute \(2\) to every term: \(2 \times a^3, 2 \times (-3a^2), 2 \times 7\).
Combining Like Terms
Combining like terms is a fundamental concept for simplifying algebraic expressions. After using the distributive property, the resulting expression may have several similar terms. We simplify the polynomial by adding or subtracting these similar terms.
- Like terms are terms that have the same variable raised to the exact power.
- In our exercise, once we distributed all terms, we had \(a^4, -3a^3, 7a\) from one set and \(2a^3, -6a^2, 14\) from another.
- Combine \(-3a^3\) and \(2a^3\), as these both are terms with \(a^3\), to get \(-a^3\).
Understanding Algebraic Expressions
An algebraic expression is a mathematical phrase that includes numbers, variables, and operation symbols. Understanding these expressions is fundamental for manipulating and solving equations.
- Variables, like \(a\), serve as placeholders that represent numbers. These can vary and are typically used to generalize math problems.
- Expressions can be added, subtracted, multiplied, and divided, as we have done in this exercise.
- Our exercise started with the expression \((a+2)(a^3 - 3a^2 + 7)\), a typical algebraic expression formed by two multiplied polynomials.