Chapter 12: Problem 19
Simplify each of the given expressions. (a) \(\sqrt{(-2)(-8)}\) (b) \(\sqrt{-2} \sqrt{-8}\)
Short Answer
Expert verified
(a) 4 and (b) -4.
Step by step solution
01
Simplify the Inside of the Square Root for (a)
In the expression \( \sqrt{(-2)(-8)} \), first simplify the multiplication inside the square root. Here, \((-2) \times (-8) = 16\). Thus, the expression simplifies to \( \sqrt{16} \).
02
Find the Square Root for (a)
Now, find the square root of the simplified number. \( \sqrt{16} = 4 \). Therefore, the simplified form of the expression is \( 4 \).
03
Simplify Each Square Root Factor for (b)
For \( \sqrt{-2} \sqrt{-8} \), recognize that each term under the square root is negative. Rewrite each square root in terms of \( i \), where \( i = \sqrt{-1} \). Thus, \( \sqrt{-2} = i \sqrt{2} \) and \( \sqrt{-8} = i \sqrt{8} \).
04
Simplify and Combine the Result for (b)
Multiply the results from Step 3: \( (i \sqrt{2})(i \sqrt{8}) = i^2 \times \sqrt{2 \times 8} = -1 \times \sqrt{16} \). Simplify \( \sqrt{16} = 4 \), leading to \( -1 \times 4 = -4 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Simplifying Expressions
Simplifying expressions is a fundamental concept in algebra that helps us make complex problems easier to handle. At its core, simplifying involves rewriting an expression in a way that is more straightforward or convenient. Often, this means condensing multiple terms into a single term.
- Start by consolidating any like terms. This means combining terms that have the same variable parts.
- When dealing with operations like multiplication and addition, follow the order of operations: parentheses, exponents, multiplication & division, and addition & subtraction (PEMDAS).
- If you encounter complex expressions within parentheses, simplify the inside first.
Square Roots
Understanding square roots is essential in both algebra and higher-level mathematics. A square root of a number is a value that, when multiplied by itself, gives the original number. This operation is denoted by the symbol \( \sqrt{} \).
- Basic square roots include numbers like \( \sqrt{4} = 2 \) because \( 2 \times 2 = 4 \).
- Finding the square root of perfect squares, like 16 or 25, is straightforward since they result in whole numbers.
- When dealing with negative numbers, like \( \sqrt{-1} \), introduce complex numbers. This is where \( i \), the imaginary unit, becomes useful.
Complex Numbers
Complex numbers expand the concept of numbers used in calculations and include a real part and an imaginary part. This allows for solutions to equations that do not have real-number solutions.
- The imaginary unit \( i \) is defined as \( i = \sqrt{-1} \), meaning \( i^2 = -1 \).
- Complex numbers are presented as \( a + bi \), where \( a \) and \( b \) are real numbers.
- Addition and subtraction of complex numbers involve combining like terms (real with real, imaginary with imaginary).